Tag: Zoology

Tel Aviv Bats Have More Fun

More adventurous than their rural counterparts, fruit bats in Tel Aviv enjoy what the city has to offer.

Urbanization processes tend to lead animals to leave the city, but some animals are able to thrive in an urban domain. A new Tel Aviv University study found that fruit bats, just like humans, are able to adapt to a variety of environments, including the city and the countryside.

Prof. Yossi Yovel: “How animals cope with urbanization is one of the most central and important questions in ecological research today. Understanding the ways in which animals adapt to urban areas can help us in our conservation efforts. The urban environment is characterized by much fragmentation, and we currently have little understanding of how animals, especially small animals, like the bats, move and fly in such areas.”

The City Bat and the Country Bat

The urban environment is fundamentally different from the rural environment in terms of the diversity and accessibility of food. Although the city has a larger variety of trees per area, there are many challenges that bats have to face, such as buildings and humans. In rural areas, on the other hand, most of the trees are concentrated in orchards without barriers, but have less diversity – the trees are mostly of one type.

Because of the environmental differences between the city and the country with regards to the distribution and variety of fruit trees, the nature of the bats’ movement when foraging in these areas differs as well. In this new study, the researchers compared the nature of the movement of rural bats and city bats as they foraged for food, using tiny GPS devices to track the bats to see if the way they moved while searching for food was affected by their living environment, or the environment in which they were foraging.

The study was led by research student Katya Egert-Berg, under the guidance of aforementioned Prof. Yossi Yovel, head of Tel Aviv University’s Sagol School of Neuroscience and a faculty member of the School of Zoology in The George S. Wise Faculty of Life Sciences and The Steinhardt Museum of Natural History, as well as a recipient of the 2021 Kadar Family Award for Outstanding Research. The study was published in the journal BMC Biology.

Enjoying their Meals in the Big City

The researchers found that the fruit bats hunting for food in the city are much more exploratory, enjoy the abundance of the urban environment, visit a variety of fruit trees every night, and feed from a wide a variety of trees. In contrast, the rural bats focus on only one or two fruit trees each night. Moreover, the researchers found that among the rural bats who rest in the countryside, there were many who left their rural homes every night in search of food in the city, and then flew back to the country after their meal. During their stay in the city, such bats share the same flight patterns as those of the bats that live in the city around the clock.

The study’s findings led the researchers to assess that even bats that live in rural environments their entire lives will be able to orient themselves in an urban, industrialized environment. They explain that there are animal species that are flexible – for them, the ability to adapt to a new and unfamiliar environment such as an urban settlement is an acquired skill. Such species, of which the fruit bats are an example, will in many cases be able to adapt to life in urban areas.

Featured image: A Tel Aviv bat in action. Photo: S. Greif

Where Have All the Birds Gone?

Humans Behind Extinction of Hundreds of Bird Species Over the Last 50,000 Years.

A new study from Tel Aviv University and the Weizmann Institute revealed that over the last 20,000-50,000 years, birds have undergone a major extinction event, inflicted chiefly by humans, which caused the disappearance of about 10%-20% of all avian species. The vast majority of the extinct species shared several features: they were large, they lived on islands, and many of them were flightless.

The main cause for extinction of species by humans today has evolved from being hunting to the destruction of the animals’ natural habitats, but the researchers hope their findings will serve as warning signals regarding bird species currently threatened with extinction.

The study was led by Prof. Shai Meiri of the School of Zoology at The George S. Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History at Tel Aviv University, and Amir Fromm of the Weizmann Institute of Science. The paper was published in the Journal of Biogeography.

Human-Inflicted Extinction

Prof. Meiri: “We conducted a comprehensive review of scientific literature, and for the first time collected quantitative data on the numbers and traits of extinct species of birds worldwide. Those that became extinct in the last 300 years or so are relatively well known, while earlier species are known to science from remains found in archaeological and paleontological sites worldwide. Altogether we were able to list 469 avian species that became extinct over the last 50,000 years, but we believe that the real number is much higher.”

The researchers believe that the vast extinction was caused primarily by humans who hunted the birds for food, or by animals brought to islands by humans – that fed on the birds and/or their eggs. This assumption is based on the fact that the greater part of bird remains was found on human sites, apparently belonging to birds consumed by the inhabitants, and in most cases the extinctions occurred shortly after the arrival of humans.

Coveted Targets for Hunters

Most extinct species shared three major features:

  1. About 90% of them lived on islands – When humans arrived on the island, the birds were hunted by them, or fell victim to other animals introduced by humans, such as pigs, rats, monkeys, and cats.
  2. Most extinct bird species were large, some very large – The body mass of the extinct species was found to be up to 10 times as large as that of surviving species. The larger birds provided humans with a great quantity of food, thus they were a preferred target for hunters. Previous studies have found a similar phenomenon among mammals and reptiles, especially lizards and turtles that lived on islands: the larger ones were hunted by humans and became extinct.
  3. A large portion of the extinct bird species were flightless, and often unable to escape their pursuers – The study found that the number of flightless bird species that became extinct is double the number of flightless species still existing today; all in all, 68% of the flightless bird species known to science became extinct. One of the better-known examples is the moa bird in New Zealand: 11 species of moa became extinct within 300 hundred years, due to hunting by humans

Prof. Meiri: “Our study indicates that before the major extinction event of the past millennia, many more large, even giant, as well as flightless avian lived on our globe, and the diversity of birds living on islands was much greater than today. We hope that our findings can serve as warning signals regarding bird species currently threatened with extinction, and it is therefore important to check whether they have similar features. It must be noted, however, that conditions have changed considerably, and today the main cause for extinction of species by humans is not hunting but rather the destruction of natural habitats.”

Featured image: Bird species at the Zoological Garden

Inside a bat’s brain

Prof. Yaniv Assaf and Prof. Yossi Yovel are working together on a unique collection of brain scans of different mammals

It’s a chicken versus egg scenario: Does behavior build a neural network or does the design of a brain network dictate behavior? It turns out that they both influence each other.

“Evolutionary science holds that particular behaviors drives the brain to develop and evolve in a particular way. Later, brain networks may drive behavior,” explains Prof. Yossi Yovel of the Department of Zoology, George S. Wise Faculty of Life Sciences. Yovel specializes in bat echolocation – the location of objects by reflected sound – at his Bat Lab of Neuro-Ecology. 

A number of years ago he approached his former MSc advisor, Prof. Yaniv Assaf, Head of the Department of Neurobiology, with a surprising request. Yovel sought to draw on Assaf’s expertise in MRI imaging techniques to scan the brains of wild bats. Could the images show how bats’ use of sound rather than vision to navigate the world influences the development of their neural networks? “I focus on human brain imaging,” says Assaf. “Now, five years later, we have scanned over 100 species – all expired of natural causes – including many species of bats, of course,” Assaf continues with a nod to Yovel. “We use the MRI machine after hours so as not to interfere with ongoing research, and we have found that, yes, bat brain networks have highly developed aural – rather than visual – networks.”

From bats to all mamals

What began as a scientific hobby has become a scientific first. The scans, which are specially calibrated to show the design and function of brain microstructure, pathways, and networks, reveal the principles governing the mammalian brain.

“Like the internet and other computer networks, or road and transportation systems, the brain is a network. The brain’s two hemispheres are connected with fibers. Our scans show that mammals with a greater number of inter-hemisphere connecting fibers will have, inversely, poorer connectivity within the hemisphere itself and vice-versa,” says Assaf. “This information can influence how networks are constructed.”

The true story of the autistic man who inspired the film Rain Man illustrates this phenomenon: The hemispheres of his brain were completely unconnected. The local network in each hemisphere was so strong that he could perform complex computations within seconds. But the lack of connection between hemispheres affected his function and behavior. We need a mix of both for a functional, strong network.

Access for researchers worldwide

”While evolutionary scientists are certainly interested in our scans, it is mathematicians and computer scientists working on smart, efficient computer networks and artificial intelligence who are the most excited,” says Assaf.

Yovel continues, “When people hear about our project at conferences or by word of mouth, they immediately want to see our findings. But we are not yet ready. We aim to scan 10% of all mammals, which means about 500 species including those transported from abroad, which will be very costly. We need graduate students to help build the collection more quickly. We aim to create the only collection of its kind worldwide – a digital collection of scans at the Steinhardt Museum of Natural History that can be accessed by scientists around the world.”

Featured image: Prof. Yossi Yovel and Prof. Yaniv Assaf 

Seahorses – Slow, but Fierce

Terrible swimmers with incredible preying capability.

Seahorses are not exactly Olympic swimmers, in fact they’re considered to be particularly poor swimmers. Despite being relatively slow, however, they are adept at preying on small, quick-moving animals. In a new study conducted at Tel Aviv University, researchers have succeeded in characterizing the incredible preying capability of seahorses, discovering that they can move their head up at the incredible speed of 0.002 seconds. The rapid head movement is accompanied by a powerful flow of water that snags their prey right into the seahorse’s mouth. How was this spring mechanism formed? When did it develop? The researchers hope the recent study will lead to further studies designed to help solve the riddle of spring fish.

The study was led by Prof. Roi Holzman and the doctoral student Corrine Jacobs of the School of Zoology at The George S. Wise Faculty of Life Sciences and the Steinhardt Museum of Natural History at Tel Aviv University, and was conducted at the Interuniversity Institute for Marine Sciences in Eilat. The study was published in the Journal of Experimental Biology.

Springing to Action

The researchers explain that seahorses are fish that possess unique properties such as male ‘pregnancy’, square tail vertebrae, and of course the unique eating system. For most of the day, seahorses are anchored with their tail to seaweeds or corals with their head tilted downward, close to their body. However, when they detect prey passing over them, they lift their head at incredible speed and catch it. According to Prof. Holzman, while preying, seahorses turn their body into a kind of spring: using their back muscles, they stretch an elastic tendon, and use their neck bones as a ‘trigger’, just like a crossbow. The result is faster than even the fastest muscle contraction found anywhere in the animal world.

However, until now it was not clear how the spring-loaded mechanism enabled seahorses to actually eat. Just as anyone who tries to remove a fly from a cup of tea knows, water is a viscous medium and the fish needs to open its mouth to create a flow that draws the prey in. But how do seahorses coordinate snagging in prey with their head movement?

In their recent study, researchers from Tel Aviv University succeeded in characterizing and quantifying seahorse movement by photographing their attack at a speed of 4,000 images per second, and using a laser system for imaging water flows. This measurement showed that the ‘crossbow’ system serves two purposes: facilitating head movement and generating high velocity suction currents – 10 times faster than those of similar-sized fish. These advantages enable seahorses to catch particularly elusive prey.

Evolution of the Spring Mechanism

The new measurements also help shed light on the ecology of various species of seahorses, distinguished from each other by the length of their noses. “Our study shows that the speed of head movement and suction currents are determined by the length of a seahorse’s nose”, Prof. Holzman added. “From the evolutionary aspect, seahorses must choose between a short nose for strong suction and moderate head raising, or a long nose for rapid head raising and weaker suction currents. This choice, of course, corresponds to the available diet: long-nosed species catch smaller, quicker animals whereas short-nosed species catch heavier, more ponderous ones.”

 

Prof. Roi Holzman hopes the recent study will lead to further studies to help solve the riddle of spring fish

According to Prof. Holzman, seahorses are not the only instance of the impressive spring mechanism. Actually, seahorses are counted among the family of fish bearing the appropriate scientific name Misfit Fish, including species such as alligator pipefish, shrimpfish, and cornetfish or flutemouths.

“These fish are called that because of their odd shape which enables stretching their body into a spring. The big question applies to the evolution of the spring mechanism, how it was formed and when it developed. I hope our recent study will lead to further studies designed to help solve the riddle of spring fish”. 

Why Do Bats Fly Into Walls?

A sensory misperception – like people bumping into a glass wall

Why do bats fly into walls, even though they can hear them? Researchers at Tel Aviv University conducted an experiment in which they released dozens of bats in a corridor blocked by objects of different sizes, made of different materials. To their surprise, the researchers discovered that the bats collided with large sponge walls (that produce a weak echo) as if they did not exist. The bats’ behavior suggested that they did this even though they had detected the wall with their sonar system, indicating that the collision did not result from a sensory limitation, but rather from an acoustic misperception. The researchers hypothesize that the unnatural combination of a large object (wall) and a weak echo disrupts the bats’ sensory perception and causes them to ignore the obstacle (much like people who bump into transparent walls).

The study was led by Dr. Sasha Danilovich then a PhD student in the lab of Prof. Yossi Yovel, Head of the Sagol School for Neuroscience and faculty member at the School of Zoology at the George S. Wise Faculty of Life Sciences. Other participants included Dr. Arian Bonman and students Gal Shalev and Aya Goldstein of the Sensory Perception and Cognition Laboratory at the School of Zoology and the Sagol School of Neuroscience. The paper was published in PNAS.

At the next stage of the experiment, the researchers methodically changed the features of the echoing objects along the corridor in terms of size, texture and echo intensity. They concluded that the bats’ acoustic perception depends on a coherent, typical correlation of the dimensions with objects in nature. For example: large object- strong echo; small object – weak echo.

“Bats excel in acoustic perception. They are able to detect objects as tiny as mosquitoes, using sound waves,” explains Prof. Yovel. “Using echolocation they can calculate the 3-dimensional location of both small and large objects, perceiving their shape, size and texture. To this end a bat’s brain processes various acoustic dimensions from the echoes returning from the object (such as frequency, spectrum and intensity). This perception is based on several senses that combine many different dimensions, such as color and shape.”

In addition, the researchers at TAU discovered that bats are not born with this ability. Repeating the experiment with young bats they found that they do not fly into walls.  The study also found that adult bats can quickly learn the new correlations among the dimensions.

“By presenting the bats with objects whose acoustic dimensions are not coherent, we were able to mislead them, creating a misconception that caused them to repeatedly try to fly through a wall, even though they had identified it with their sonar. The experiment gives us a peek into how the world is perceived by these creatures, whose senses are so unique and different from ours,” says Sasha Danilovich.

Like Teenagers on Vacation

Light pollution can impair crickets’ reproductive process and threaten their survival.

A joint study conducted by researchers from Tel Aviv University and the Open University of Israel revealed that exposing male crickets to artificial light at night (ALAN) can impair their activity cycles. According to the researchers, nocturnal chirping is the male’s way of calling females to come and mate with him, and its disruption can interfere with reproduction processes and even endanger the entire species. Previous studies worldwide have shown that light pollution is harmful to many species of animals and plants. The researchers call for reducing ALAN as much as possible to enable coexistence in the night environment.

Humans are Driving Away the Darkness

Keren Levy of the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University explains: “The distinction between day and night, light and darkness, is a major foundation of life on earth. But humans, as creatures of the day who fear the dark, disrupt this natural order: they produce artificial light that drives away the darkness and allows them to continue their activities at night.”

Levy explains that today, more than 80% of the world population live under light pollution, and the overall extent of artificial light at night rises by 5% every year. This negatively impacts the environment and affects natural behaviors that have developed over millions of years of evolution. The artificial light at night affects the length and quality of sleep of many animals, leads to high mortality, and changes the activity cycles of many creatures. For example, dung beetles, that navigate using the Milky Way, lose their way when light pollution increases; sea turtles hatchlings seek the brightest surface in sight – supposedly the sea, and reach the nearby promenade instead; to mention just two of many examples.

Off-Tune Crickets

In the current study the researchers examined the impact of light pollution on the field cricket, a nocturnal insect whose chirping can be heard during the nights of late summer – when males call for females to mate with them.

Prof. Amir Ayali, also from TAU’s School of Zoology and the Steinhardt Museum of Natural History, explains, “In nature, crickets exhibit a very regular cycle of activity. Chirping behavior, calling for females, occurs at sunset and during the night, ending in the morning. We exposed field crickets to different levels of lifelong ALAN and observed its impact on two fundamental behaviors: chirping and locomotion.”

The researchers monitored dozens of crickets that were exposed throughout their lives (from egg to adult stage) to four types of light conditions. They found that crickets whose light-dark cycle is disrupted behave like teenagers on vacation: active or asleep according to their own inner clock or lacking any rhythm whatsoever.

“In fact,” adds Keren Levy, “light pollution induced by humankind impacts the field cricket and evokes loss of synchronization within the individual, on the population level, and between the population and the environment. Our findings on ALAN-induced changes in calling song patterns may possibly impair female attraction and reproduction in this species. Our results are in accord with many other studies demonstrating the severe impacts of low levels of ALAN on nature.”

Levy urges us all to help protect our environment and surroundings by turning off the lights in our backyards, on the terrace, in parking lots, and wherever possible: “Help us bring the night and the milky way back into our lives and enable nightly coexistence with the creatures around us.”

The study was led by Prof. Amir Ayali and Keren Levy of the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University and Prof. Anat Barnea of the Department of Natural and Life Sciences at the Open University. Yoav Wegrzyn from Prof. Ayali’s laboratory and Ronny Efronny also took part in the study. The paper was published in Proceedings of the Royal Society B, and also mentioned in Nature.

Featured image: Prof. Amir Ayali and a small friend (Photo: Jonathan Blum)

Coral danger: breakdown in spawning could mean extinction

Synchronized coral spawning has become erratic, endangering the long-term survival of coral species, Tel Aviv University researchers say

Coral reefs are among the most diverse and productive ecosystems on our planet. But due to climate change and other human stressors, reef-building corals that reproduce by means of broadcast-spawning — the simultaneous release of eggs and sperm into open water — may now be under threat of extinction.

A new Tel Aviv University study finds that the highly synchronized, iconic spawning events of certain reef-building corals in the Gulf of Eilat/Aqaba, Red Sea, have completely changed over time and lost their vital synchrony, dramatically reducing chances of successful fertilization.

According to the research, led by Prof. Yossi Loya and PhD candidate Tom Shlesinger of TAU’s School of Zoology and published in Science, the breakdown in coral spawning synchrony has led to a dearth of new recruits and stagnant aging populations, creating circumstances for extinction.

It’s all in the timing

“Coral spawning, often described as ‘the greatest orgy in the world,’ is one of the greatest examples of synchronized phenomena in nature,” explains Prof. Loya. “Once a year, thousands of corals along hundreds of kilometers of a coral reef release their eggs and sperm simultaneously into the open water, where fertilization will later take place. Since both the eggs and the sperm of corals can persist only a few hours in the water, the timing of this event is critical.”

Successful fertilization, which can take place only within this narrow time window, has led to the evolution of a precise spawning synchrony. Such synchronicity relies on environmental cues: sea temperature, solar irradiance, wind, the phase of the moon and the time of sunset.

In 2015, the researchers initiated a long-term monitoring of coral spawning in the Gulf of Eilat/Aqaba. Over four years, they performed 225 night field surveys lasting three to six hours each during the annual coral reproductive season from June to September and recorded the number of spawning individuals of each coral species.

“We found that, in some of the most abundant coral species, the spawning synchrony had become erratic, contrasting both the widely accepted paradigm of highly synchronous coral spawning and studies performed on the exact same reefs decades ago,” says Shlesinger.

Extinction through reproductive failure

The researchers then investigated whether this breakdown in spawning synchrony translated into reproductive failure. They mapped thousands of corals within permanent reef plots, then revisited these plots every year to examine and track changes in the coral community — i.e., how many corals of a given species had died compared with new juveniles recruited to the reef.

“Although it appeared that the overall state of the coral reefs at Eilat was quite good and every year we found many new corals recruiting to the reefs, for those species that are suffering from the breakdown in spawning synchrony, there was a clear lack of recruitment of new juvenile generations, meaning that some species that currently appear to be abundant may actually be nearing extinction through reproductive failure,” says Shlesinger.

The future of corals?

“Several possible mechanisms may be driving the breakdown in spawning synchrony that we found,” Prof. Loya concludes. “For example, temperature has a strong influence on coral reproductive cycles. In our study region, temperatures are rising fast, at a rate of 0.31 degrees Celsius per decade, and we suggest that the breakdown in spawning synchrony reported here may reflect a potential sublethal effect of ocean warming. Another plausible mechanism may be related to endocrine (hormonal) disrupting pollutants, which are accumulating in marine environments as a result of ongoing human activities that involve pollution.”

“Regardless of the exact cause leading to these declines in spawning synchrony, our findings serve as a timely wake-up call to start considering these subtler challenges to coral survival, which are very likely also impacting additional species in other regions,” says Shlesinger. “On a positive note, identifying early-warning signs of such reproductive mismatches will contribute to directing our future research and conservation efforts toward the very species that are at potential risk of decline, long before they even display any visible signs of stress or mortality.”

A House is Not a Home Without a Pet

TAU law students are helping elderly citizens and their pets move to senior homes.

Many senior citizens have to part with their beloved pets just when they need them the most: when they leave their homes and transition to live in public housing for the elderly. In many of these governmental institutions, pets are still not allowed – and when they are, the policy is not always implemented. This can cause a painful situation which may harm the mental and physical wellbeing of senior citizens, and affect the welfare of the animals (often senior as well) that find themselves homeless and separated from their loving caretakers.

We have some positive news: There are good people out there who are pro-actively seeking to protect the rights of pet caretakers, as well as the pets’.

Who? Students of The Buchmann Faculty of Law who work through the Clinic for Environmental Justice and the Protection of Animal Rights, an integral part of the The Coller-Menmon Animal Rights and Welfare Program, Israel’s leading and most comprehensive academic program on animal law, at the Faculty of Law. We do realize that’s a mouthful and warrants some further explanation…

Protecting Animals’ Rights

The Clinic for Environmental Justice has been handling a range of environmental issues since 2001. In 2017, it expanded its operations to include the protection of animals’ rights. Through their work at the Clinic, law students get to practice drafting applications, precedents and position papers, closely accompanied by top academics and clinical facilitators from Israel’s legal system. 

Dr. Orit Hirsch-Matsioulas researches human-animal relations. She is a post-doctoral fellow of The Coller-Menmon Animal Rights and Welfare Program and one of the founders of The Community for Human-Animal Studies Israel (HASI). Together with Adv. Amnon Keren, Program Coordinator and Clinical Instructor at the Clinic, she made the rights of the elderly and their pets one of the Clinic’s lead projects.

Both Granny and Kitty Benefit

The project was significantly accelerated when the Clinic decided to handle the appeal of a group of senior citizens who were told they were not allowed to bring their pets to their public housing apartments. “The rights of elderly people were violated,” says Dr. Hirsch-Matsioulas. “Some of them decided against moving because they did not want to part with their pets. Noah, the umbrella organization for Israel’s animal protection associations, contacted us, and we got in touch with the Ministry of Construction and Housing to change the existing policy.”

Dr. Hirsch-Matsioulas presented the Ministry with academic studies on emotional, cognitive and health-related benefits of pet relationships for senior citizens. Moreover, she brought a new element to the attention of the Ministry officials, namely the effect of the relationship on the animals.

“We built a multidisciplinary team of people from the fields of law, social sciences, social work, gerontology (i.e. the multidisciplinary study of aging, including physical aspects as well as mental, social and societal implications) and civil society organizations, and we’re working together with the Ministry of Construction and Housing,” explains Dr. Hirsch-Matsioulas. 

A temporary policy was established, allowing for the entry and keeping of pets in all public senior homes, called בתי גיל הזהב, under the responsibility of Israel’s Ministry of Construction and Housing. It was widely agreed that this temporary right should eventually become permanent, however this is a lengthy process. 

 

Kitty and Milo also have rights. Photo: Vika Minkowitz Mualem

Focusing on Solutions

While we’re excited to share that this undertaking is, in fact, a global precedent, the process of implementing the policy has not been a smooth ride. Due to Covid restrictions, the team has not been able to enter the senior housing buildings to teach the staff about the new guidelines for successful implementation. “The doors have been opened. Now, we must focus on ensuring the optimal execution,” says Dr. Hirsch-Matsioulas. 

Dr. Hirsch-Matsioulas is compiling a report with all the issues that do or may arise. She will then proceed to examine the appropriate solutions for every listed problem, through consultation with relevant professionals. The aim is to come up with suitable solutions for the preservation of the elderly’s right to good health and a dignified life, as well as the preservation of the rights of the animals. Once completed, she will present the list to policy makers to advance the legislation, with the aim that the Ministry of Construction and Housing can adopt the law on a permanent basis. 

The arrived upon solutions will be offered, and hopefully adopted, by additional countries as well.

 

Emotional, cognitive and health benefits enjoyed by both parties. Photo: Vika Minkowitz Mualem

Across Generations and Species

“We intend to visit senior homes, observe and learn, and then to provide cultural programs with positive and educational messages on how to co-exist in a community with multiple living species,” offers Dr. Hirsch-Matsioulas.

“Education is central for promoting change, and we would like to cultivate a new atmosphere on ground through a series of lectures. Children and youth are oftentimes leading agents of change, and we may end up including the grandchildren in this effort.” 

“Beyond our firm conviction that the elderly shouldn’t have to part with their pets, that are to them like family members for all intents and purposes, the Clinic also makes sure that the animals’ interests are represented. Forced removal of an animal from a warm and loving home can cause him or her great suffering, especially in old age,” adds Adv. Keren.

“In recent years, there’s been a growing recognition in Israel of animal rights and their welfare, as key considerations in decision-making pertaining to them. We will continue to develop this trend, whereby the animal is regarded as a subject with his or her own rights, each animal representing a world of his or her own and worthy of protection in and by him- or herself.”

 

Dr. Orit Hirsch-Matsioulas and her good friend, Shenef. 

Featured image: Family and flatmates. Photo: Noah Toledano

Bats navigate just like humans – using their excellent eyesight and a cognitive map

A new study investigates the navigation capabilities of bats from birth to maturity

For the first time in history, researchers at Tel Aviv University tracked fruit bats from birth to maturity, in an attempt to understand how they navigate when flying long distances. The surprising results: Fruit bats, just like humans, build a visual cognitive map of the space around them, making use of conspicuous landmarks. In this case, bat pups from Tel Aviv University came to know the city by looking for large unique structures such as the Azrieli Towers, the Dizengoff Center etc. The groundbreaking study was conducted by Prof. Yossi Yovel, together with students Amitai Katz, Lee Harten, Aya Goldstein and Michal Handel from the Sensory Perception and Cognition Laboratory at the Department of Zoology. The paper was published in July 2020 as the cover story of the prestigious Science Magazine. “How animals are able to navigate over long distances is an ancient riddle,” explains Prof. Yovel. “Bats are considered world champions of navigation: they fly dozens of kilometers in just a few hours, and then come back to the starting point. For this study we used tiny GPS devices – the smallest in the world, developed by our team, in an experiment never attempted before: tracking bat pups from the moment they spread their wings until they reach maturity, in order to understand how their navigation capabilities develop. No such study has ever been conducted on any living creature, and the findings are very interesting.” The researchers monitored 22 fruit bat pups born in a colony raised at TAU – from infancy to maturity, tracking them as they scoured the city for food. The results show that Tel Aviv bats navigate the space around them in much the same way as the city’s human inhabitants. “Bats use their sonar to navigate over short distances – near a tree, for example,” says Prof. Yovel. “The sonar doesn’t work for greater distances. For this, fruit-bats use their vision. Altogether we mapped about 2000 bat flight-nights in Tel Aviv. We found that bats construct a mental map: They learn to identify and use salient visual landmarks such as the Azrieli Towers, the Reading Power Station and other distinct features that serve as visual indicators. The most distinct proof of this map lies in their ability to perform shortcuts. Like humans, bats at some stage get from one point to another via direct new routes not previously taken. Since we knew the flight history of each bat since infancy, we could always tell when a specific bat took a certain shortcut for the first time. We discovered that when taking new, unknown routes the bats flew above the buildings. Sending up drones to the altitude and location where a bat had been observed, we found that the city’s towers were clearly visible from this high angle. Here is another amazing example of how animals make use of manmade features.”

Why Do We Squabble Over The AC?

New study reveals the evolutionary reason why women feel colder than men.

Why do women typically bring a sweater into work while their male counterparts feel comfortable wearing short sleeves in an air-conditioned office? Researchers at Tel Aviv University’s School of Zoology offer a new evolutionary explanation for the familiar scenario and can share that this phenomenon is not unique to humans, with many male species of endotherms (birds and mammals) preferring a cooler temperature than the females. The researchers propose that males and females feel temperature differently, explaining that this is a built-in evolutionary difference between the heat-sensing systems of the two sexes, related, among other things, to the reproduction process and caring for offspring.

The study was led by Dr. Eran Levin and Dr. Tali Magory Cohen from the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University, Yosef Kiat from the University of Haifa, and Dr. Haggai Sharon, a pain specialist from Tel Aviv University’s Sackler Faculty of Medicine and the Tel Aviv Sourasky Tel Aviv Medical Center (Ichilov Hospital). The article was published in the Journal Global Ecology and Biogeography.

Separation During Breeding Season

The new study included an in-depth statistical and spatial analysis of the distribution of dozens of bird and bat species living in Israel, along with a comprehensive review of the international research literature on the subject.

A study of the research literature reveals several examples of a similar phenomenon observed in many species of birds and mammals. In migratory bird species, males spend the winter in colder areas than females (it should be noted that in birds, the segregation between the sexes takes place outside of the breeding season, since the males participate in the raising of the chicks).

Amongst many mammals, even in species that live in pairs or in mixed groups all their lives, the males prefer shade whereas the females prefer sunlight, or the males ascend to the peaks of mountains while the females remain in the valleys.

Following the literature review, the researchers conducted their own research. They sampled information collected in Israel over the course of nearly 40 years (1981-2018) on thousands of birds from 13 migratory bird species from 76 sites (data from Birdlife Israel and the Steinhardt Museum of Natural History) and 18 species of bats from 53 sites (data from the researchers and the Society for the Protection of Nature.) In total, the study included more than 11,000 individual birds and bats, from Mount Hermon in the north to Eilat in the south.

The reasoning behind the choice of birds and bats for the study is the fact that they fly and are therefore highly mobile, and the researchers hypothesized that the spatial separation between the sexes – sometimes extending to different climatic zones – would be particularly clear in these groups. Moreover, Israel’s significant climate diversity allowed them to study individual animals of the same species that live in very different climatic conditions.

 

Illustrative Photo: Bats in Cave

The findings of the study clearly demonstrated that males prefer a lower temperature than females, and that this preference leads to a separation between the sexes at certain periods during the breeding cycles, when the males and females do not need, and may even interfere, with each other.

Dr. Levin: “Our study has shown that the phenomenon is not unique to humans; among many species of birds and mammals, females prefer a warmer environment than males, and at certain times these preferences cause segregation between the two species. In light of the findings, and the fact that this is a widespread phenomenon, we have hypothesized that what we are dealing with is a difference between the females and males’ heat-sensing mechanisms, which developed over the course of evolution. This difference is similar in its essence to the known differences between the pain sensations experienced by the two sexes, and is impacted by differences in the neural mechanisms responsible for the sensation and also by hormonal differences between males and females.”

Dr. Levin, who among other things studies the physiology and behavior of bats, noted in his previous studies that during the breeding season males and females tend to segregate, with the males inhabiting cooler areas. For example, entire colonies in caves on the slopes of Mount Hermon are composed of only males during the breeding season, while in the warmer area of the Sea of Galilee there are mainly females, who give birth and raise their pups there.

Dr. Magory Cohen notes that this difference has a number of evolutionary explanations. First, the separation between males and females reduces competition over resources in the environment, and keeps away males who may be aggressive and endanger the babies. Furthermore, many female mammals must protect their offspring at a stage when they are not yet able to regulate their body temperature on their own, so they developed a preference for a relatively warm climate.

Giving Each Other Some Space

The phenomenon can also be linked to sociological phenomena observed in many animals and even in humans; in a mixed environment of females and males the females tend to have much more physical contact between themselves, whereas males maintain more distance and shy away from contact with each other.

It appears the difference in thermal sensation did not come about so we can argue with our partners over the air conditioning. Rather, we are meant to give each other some space so that each person can enjoy some peace and quiet. Question is, who gets the couch?

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