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Posts Tagged ‘mobulids’


Brain and behavior

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

Behavior Brief

A round-up of recent discoveries in behavior research

By Catherine Offord | March 25, 2016

http://www.the-scientist.com/?articles.view/articleNo/45665/title/Behavior-Brief

Manta in the mirror

http://www.the-scientist.com/images/News/March2016/mantamain.jpg

The mirror self-recognition (MSR) test is commonly used to evaluate nonhuman animals’ self-awareness, and has been reportedly passed by several mammals and birds including apes, elephants, dolphins, and magpies. According to a study published earlier this month (March 11) in The Journal of Ethology, there’s now evidence to add manta rays to that list.

Contingency checking and self-directed behaviors in giant manta rays: Do elasmobranchs have self-awareness?

Csilla Ari  , Dominic P. D’Agostino     Journal of Ethology   11 March 2016: 1-8    http://link.springer.com/article/10.1007%2Fs10164-016-0462-z    doi:10.​1007/​s10164-016-0462-z

Elaborate cognitive skills arose independently in different taxonomic groups. Self-recognition is conventionally identified by the understanding that one’s own mirror reflection does not represent another individual but oneself, which has never been proven in any elasmobranch species to date. Manta rays have a high encephalization quotient, similar to those species that have passed the mirror self-recognition test, and possess the largest brain of all fish species. In this study, mirror exposure experiments were conducted on two captive giant manta rays to document their response to their mirror image. The manta rays did not show signs of social interaction with their mirror image. However, frequent unusual and repetitive movements in front of the mirror suggested contingency checking; in addition, unusual self-directed behaviors could be identified when the manta rays were exposed to the mirror. The present study shows evidence for behavioral responses to a mirror that are prerequisite of self-awareness and which has been used to confirm self-recognition in apes.

X-RAY MAG: How did you become interested in studying the behavior of manta rays?

CA: I knew that I wanted to dedicate my life to study and protect marine life since I was 13 years old. It was during a family vacation in Croatia when I first had the chance to try scuba diving. I was so mesmerized by the experience that when I surfaced I decided to try to find out more about this magical world. I became especially fascinated by the majestic and mysterious manta rays after watching a nature documentary, soon after this first dive. It described how little we know about them and how vulnerable they are.

But growing up in Hungary, a landlocked country, I did not have much option to pursue my dream as a marine biologist, so I got my master’s degree in zoology and my doctorate in neurobiology, while volunteering at oceanography institutes in different countries during the summers. During my PhD studies, I worked on the neuroanatomy and neurohistology of several shark and ray species, including mobulids (mantas and mobulas). During these years, I had the chance to explore the brain structures of mantas and mobulas, which reflected some very unique and surprising features. It was the unusual enlargement of some of their brain parts that got me interested in focusing on their behavior.

“Manta rays are likely the first fish species found to exhibit self-awareness, which implies higher order brain function, as well as sophisticated cognitive and social skills,” study coauthor Csilla Ari told X-Ray Mag.

COGNITION AND SELF AWARENESS IN MANTA RAYS   

Observing two rays in a tank at the Atlantis Aquarium in the Bahamas, the researchers noticed that the animals changed their behavior when a mirror was placed on one of the walls. New behaviors included apparently checking out their fins (see this video) and blowing bubbles at their reflections.     https://youtu.be/LQ1KErB_2oU

X-RAY MAG: What were the findings that caused you to conclude that these animals are using cognition?

CA: Animal cognition, often referred to as animal intelligence, is an exciting scientific field that attempts to describe the mental capacity of an animal. It developed from the field of comparative psychology and it includes exciting research questions, such as perception, attention, selective learning, memory, spatial cognition, tool use, problem solving or consciousness.

There are no easy ways to test these on manta rays, but I found a widely-used and well-established test that can give us insight on their cognitive abilities. The mirror self-recognition (MSR) test is considered to be a reliable behavioral index to show the animal’s ability for self-recognition/self-awareness. Recognizing oneself in a mirror is a very rare capacity among animals. Only a few, large-brained species have passed this test so far, including Asian elephants, bottlenose dolphins and great apes, but no fish species so far.

So, employing a protocol adapted from primates and bottlenose dolphin MSR studies, I exposed captive manta rays to a large mirror and recorded their behavior. The manta rays showed significantly higher frequency of repetitive behavior, such as circling at the mirror or high frequency cephalic fin movements when the mirror was placed in the tank. Contingency checking and self-directed behavior included body turns into a vertical direction, exposing the ventral side of the body to the mirror while staying visually oriented to the mirror. Most surprisingly, such self-directed behaviors were sometimes accompanied with bubble blowing front of the mirror and sharp downward swims.

“This new discovery is incredibly important,” Marc Bekoff of the University of Colorado in Boulder who was not involved in the study told New Scientist. “It shows that we really need to expand the range of animals we study.”

But the MSR test’s developer, Gordon Gallup of the State University of New York at Albany, told New Scientist that the observed movements might reflect curious, rather than self-aware, behavior. “Humans, chimpanzees, and orangutans are the only species for which there is compelling, reproducible evidence for mirror self-recognition,” he said.

Manta rays are first fish to recognise themselves in a mirror  https://www.newscientist.com/article/2081640-manta-rays-are-first-fish-to-recognise-themselves-in-a-mirror

Manta Ray (Manta birostris) feeding on plankton in current, Sangalakki Island, Borneo

Manta ray hears the dinner bell    Norbert Wu/Minden Pictures/FLPA

Giant manta rays have been filmed checking out their reflections in a way that suggests they are self-aware.

Harmless but zippy

Rattlesnakes and other vipers are well-known for their lightning-quick bites, but nonvenomous snakes may be just as speedy, according to a study published this month (March 15) in Biology Letters.

Debunking the viper’s strike: harmless snakes kill a common assumption

David A. Penning, Baxter Sawvel, Brad R. Moon

“There’s this kind of pre-emptive discussion that [vipers] are faster,” study coauthor David Penning of the University of Louisiana, Lafayette, told Smithsonian. But, he added, “as sexy as the topic sounds, there’s not that much research on it.”

To Scientists’ Surprise, Even Nonvenomous Snakes Can Strike at Ridiculous Speeds  By Marcus Woo

The Texas rat snake was just as much of a speed demon as deadly vipers, challenging long-held notions about snake adaptations

http://www.smithsonianmag.com/science-nature/scientists-surprise-even-nonvenomous-snakes-can-strike-ridiculous-speeds-180958452

Texas Rat Snake

Read more: http://www.smithsonianmag.com/science-nature/scientists-surprise-even-nonvenomous-snakes-can-strike-ridiculous-speeds-180958452/#XCyQyDlTqj1JWi14.99

To put the assumption to the test, Penning and his colleagues used a high-speed camera to film strikes from three snake species—the western cottonmouth and the western diamond-backed rattlesnake (both vipers), and a relatively harmless Texas rat snake that kills its prey using constriction.

When a snake strikes, it literally moves faster than the blink of an eye, whipping its head forward so quickly that it can experience accelerations of more than 20 Gs. “It’s the lynchpin of their strategy as predators,” says Rulon Clark at San Diego State University. “Natural selection has optimized a series of adaptations around striking and using venom that really helps them be effective predators.”

When Penning and his colleagues compared strike speeds in three types of snakes, they found that at least one nonvenomous species was just as quick as the vipers. The results hint that serpents’ need for speed may be much more widespread than thought, which raises questions about snake evolution and physiology.  They compared the western cottonmouth and the western diamond-backed rattlesnake, which are both vipers, and the nonvenomous Texas rat snake. They put each snake inside a container and inserted a stuffed glove on the end of a stick. They waved the glove around until the animal struck, recording the whole thing with a high-speed camera. The team tested 14 rat snakes, 6 cottonmouths and 12 rattlesnakes, recording several strikes for each individual.

The recordings revealed that although the highest head acceleration—279 meters per second squared, or nearly 29 g—did indeed come from a rattlesnake, one of the rat snakes followed close behind, accelerating its head at 274 meters per second squared.   All the snakes turned out to be speed demons, the team reports this week in Biology Letters. The rattlesnake scored the highest measured acceleration, at 279 meters per second squared. But to their surprise, the nonvenomous rat snake came in a close second at 274 meters per second squared. That’s lightning-quick, considering that a Formula One race car accelerates at less than 27 meters per second squared to go from 0 to 60 in just one second.

“I was really surprised, because this comparison hadn’t been made before,” Rulon Clark of San Diego Statue University who was not involved in the work told Smithsonian. “It’s not that the vipers are slow, it’s that this very high-speed striking ability is something that seems common to a lot of snake species—or a wider array than people might’ve expected.”

Penning told Discover Magazine that the results make sense, since even nonvenomous snakes have to catch their food. “Prey are not passively waiting to be eaten by snakes,” he said.

Even Harmless Snakes Strike at Deadly Speed

Rather than offering the snakes some sacrificial prey animals, the researchers baited the snakes into striking in self-defense. They used a stuffed glove on a stick. The glove would move around the snake until the animal realized the glove was “clearly not going away,” Penning says, and struck at it. High-speed cameras and mirrors captured these attacks, which happened in the blink of an eye.

Early learning

Emerging evidence suggests that both humans and superb fairywrens begin learning the vocal patterns of their mothers even before birth. Now, a study published this month (March 16) in The Auk: Ornithological Advances indicates that the same is true of the red-backed fairywren, offering the possibility of studying the phenomenon across related species.

“Fairywrens have become a new model system in which to test new dimensions in the ontogeny of parent-offspring communication in vertebrates,” study coauthor Mark Hauber of New York City’s Hunter College said in a statement.

Following on their previous discovery of prenatal learning in superb fairywrens, the researchers compared the structure of nestling calls in the red-backed fairywren to the calls of the birds’ mothers. The team found that the more calls per hour that nestlings received when in the egg, the higher the similarity to maternal calls after hatching. (The number of calls received during the nestling period had no effect on call similarity.)

“Prenatal vocal learning has rarely been described in any animal, with the exception of humans and Australian superb fairywrens,” William Feeney of the University of Queensland, Australia, who was not involved in the work said in the statement. “This result is exciting as it opens the door to investigating the taxonomic diversity of this ability, which could provide insights into why it evolves.”

Vocal imitation of mother’s calls by begging Red-backed Fairywren nestlings increases parental provisioning

Red-backed fairywren (Malurus melanocephalus)  J WELKIN

 

Prenatal imitative learning is an emerging research area in both human and non-human animals. Previous studies in Superb Fairywrens (Malurus cyaneus) showed that mothers are vocal tutors to their embryos and that better imitation of maternal calls yields more parental provisions after hatching. To begin to test if such adaptive behavior is widespread amongst Australasian wrens in Maluridae, we investigated maternal in-nest calling patterns in Red-backed Fairywrens (Malurus melanocephalus). We first compared the structure of maternal and nestling call elements. Next, we examined how in-nest calling behavior varied with parental behaviors and ecological contexts (i.e. prevalence of brood parasitism and nest predation). All Red-backed Fairywren females called to their eggs during incubation and they continued to do so for several days after hatching at a lower rate. Embryos that received more calls per hour during the incubation period (but not the nestling period) developed into hatchlings with higher call element similarity between mother and young. Female call rate was mostly independent of nest predation but in years with more interspecific brood parasitism, nestling element similarity was greater and female call rates tended to be higher. Playback experiments showed that broods with higher element similarity to their mother received more successful feeds. The potential for prenatal tutoring and imitative begging calls in 2 related fairywren taxa sets the stage for a full-scale comparative analysis of the evolution and function of these behaviors across Maluridae and in other vocal-learning lineages.

 

Traveling junk-foodies

White storks may be addicted to junk food, in some cases making migratory trips of tens of kilometers to landfill sites during the breeding season, according to a study published earlier this month (March 15) in Movement Ecology.

“We found that the continuous availability of junk food from landfill has influenced nest use, daily travel distances, and foraging ranges,” study coauthor Aldina Franco of the University of East Anglia said in a statement. “Storks now rely on landfill sites for food—especially during the non-breeding season when other food sources are more scarce.”

Using GPS tracking, the researchers focused on 17 storks traveling between nesting and feeding areas over the course of a year. They found that most long-distance trips were made to landfill sites, and that “having a nest close to a guaranteed food supply also means that the storks are less inclined to leave for the winter,” Franco explained in the statement. “They instead spend their non-breeding season defending their highly desirable nest locations.”

“It’s clear migratory behaviors are quite plastic, in that the [storks] are adaptable and can change quickly,” Andrew Farnsworth of the Cornell Lab of Ornithology who was not involved in the work told National Geographic. He added that the new, detailed dataset will help scientists “consider how such changes in behavior may affect the future population of these birds.”

Are white storks addicted to junk food? Impacts of landfill use on the movement and behaviour of resident white storks (Ciconia ciconia) from a partially migratory population

Nathalie I. Gilbert Email authorRicardo A. CorreiaJoão Paulo Silva,…, Jenny A. Gill and Aldina M. A. Franco

Movement Ecology 2016; 4:7      http://dx.doi.org:/10.1186/s40462-016-0070-0

The migratory patterns of animals are changing in response to global environmental change with many species forming resident populations in areas where they were once migratory. The white stork (Ciconia ciconia) was wholly migratory in Europe but recently guaranteed, year-round food from landfill sites has facilitated the establishment of resident populations in Iberia. In this study 17 resident white storks were fitted with GPS/GSM data loggers (including accelerometer) and tracked for 9.1 ± 3.7 months to quantify the extent and consistency of landfill attendance by individuals during the non-breeding and breeding seasons and to assess the influence of landfill use on daily distances travelled, percentage of GPS fixes spent foraging and non-landfill foraging ranges.   Results   Resident white storks used landfill more during non-breeding (20.1 % ± 2.3 of foraging GPS fixes) than during breeding (14.9 % ± 2.2). Landfill attendance declined with increasing distance between nest and landfill in both seasons. During non-breeding a large percentage of GPS fixes occurred on the nest throughout the day (27 % ± 3.0 of fixes) in the majority of tagged storks. This study provides first confirmation of year-round nest use by resident white storks. The percentage of GPS fixes on the nest was not influenced by the distance between nest and the landfill site. Storks travelled up to 48.2 km to visit landfills during non-breeding and a maximum of 28.1 km during breeding, notably further than previous estimates. Storks nesting close to landfill sites used landfill more and had smaller foraging ranges in non-landfill habitat indicating higher reliance on landfill. The majority of non-landfill foraging occurred around the nest and long distance trips were made specifically to visit landfill.  Conclusions   The continuous availability of food resources on landfill has facilitated year-round nest use in white storks and is influencing their home ranges and movement behaviour. White storks rely on landfill sites for foraging especially during the non-breeding season when other food resources are scarcer and this artificial food supplementation probably facilitated the establishment of resident populations. The closure of landfills, as required by EU Landfill Directives, will likely cause dramatic impacts on white stork populations.

WEIRD & WILD   Junk Food-Loving Birds Diss Migration, Live on Landfill    By Brian Handwerk

Spain and Portugal’s white storks are forgoing their annual journeys to African wintering grounds, a new study says

http://news.nationalgeographic.com/2016/03/060315-storks-food-animals-science-urban-food/

You’ve heard of the staycation. Some white storks in Europe are now opting for the staygration. 

The big birds are skipping their annual trip to African wintering grounds to remain year-round in Spain and Portugal, a new study shows.

Why? They’ve developed an addiction to junk food at landfills.

“White storks used to be wholly migratory. Before the 1980s, there were no white storks staying in” Spain and Portugal, says study leader Aldina Franco, a conservation ecologist at the University of East Anglia in the U.K.

“During the 1980s, the first individuals started staying, and now we see those numbers increasing exponentially.” (Related: “Beloved Storks, Emblems of Fertility, Rebounding in France.”)

 

Unlikely allies

Israel’s barren Negev desert is home to striped hyenas and gray wolves—two large scavenger species with considerably overlapping diets. But although such conditions might be expected to create fierce competition, researchers in Israel and the U.S. have now presented evidence that—at least in some cases—these animals form alliances and may even hunt collaboratively for food. The findings were published last month (February 10) in Zoology in the Middle East.

Wolves and hyenas in the desert might “just need each other to survive, because food is so, so limited,” study coauthor Vladimir Dinets of the University of Tennessee in Knoxville told The Washington Post.

Collating observations made over the past two decades (including reports of overlapping paw prints, and sightings of hyenas among packs of wolves), the researchers note that the findings could reflect the behavior of a few, oddly behaving hyenas, or a more widespread commensal, or even cooperative, relationship between the species.

“Animal behavior is often more flexible than described in textbooks,” Dinets said in a press release. “When necessary, animals can abandon their usual strategies and learn something completely new and unexpected. It’s a very useful skill for people, too.”

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