̽��ֱ�� of Cambridge - Corina Logan

Larger brain size linked to longer life in deer

mjg209 — Wed, 14 Dec 2016 23:09:33 +0000

̽��ֱ��study, published in the Royal Society Open Science journal, shows that female red deer with larger brains live longer and have more surviving offspring than those with smaller brains. Brain size is heritable and is passed down through the generations. This is the first extensive study of individual differences in brain size in wild mammals and draws on data comparing seven generations of deer.

Across species of mammals, brain size varies widely. This is thought to be a consequence of specific differences in the benefits and costs of a larger brain. Mammals with larger brains may, for example, have greater cognitive abilities that enable them to adapt better to environmental changes or they may have longer lifespans. But there may also be disadvantages: for instance, larger brains require more energy, so individuals that possess them may show reduced fertility.

̽��ֱ��researchers, based at the ̽��ֱ�� of Cambridge's Zoology Department and Edinburgh ̽��ֱ��'s Institute of Evolutionary Biology, wanted to test if they could find more direct genetic or non-genetic evidence of the costs and benefits of large brain size by comparing the longevity and survival of individuals of the same species with different sized brains. Using the skulls of 1,314 wild red deer whose life histories and breeding success had been monitored in the course of a long-term study on the Isle of Rum, they found that females with larger endocranial volumes lived longer and produced more surviving offspring in the course of their lives.

Lead author Dr Corina Logan, a Gates Cambridge Scholar and Leverhulme Early Career Research Fellow in Cambridge's Department of Zoology, says: " ̽��ֱ��reasons for the association between brain size and longevity are not known, but other studies have suggested that larger brains are a consequence of the longer-lived species having longer developmental periods in which the brain can grow. These hypotheses were generated from cross-species correlations; however, testing such hypotheses requires investigations at the within-species level, which is what we did."

Dr Logan adds: "We found that some of the cross-species predictions about brain size held for female red deer, and that none of the predictions were supported in male red deer. This indicates that each sex likely experiences its own set of trade-offs with regard to brain size.”

̽��ֱ��study also showed that females' relative endocranial volume is smaller than that of males, despite evidence of selection for larger brains in females.

"We think this is likely due to sex differences in the costs and benefits related to larger brains," adds Dr Logan. "We don’t know what kinds of trade-offs each sex might encounter, but we assume there must be variables that constrain brain size that are sex specific, which is why we see selection in females, but not males."

Professor Tim Clutton-Brock, who set up the Rum Red Deer study with Fiona Guinness in 1972 and initiated the work on brain size, points out that the reason that this kind of study has not been conducted before is that it requires long term records of a large number of individuals across multiple generations and data of this kind are still rare in wild animals.

Reference
C.J. Logan, R. Stanley, A.M. Thompson, T.H. Clutton-Brock. Endocranial volume is heritable and is associated with longevity and fitness in a wild mammal. Royal Society Open Science; 14 Dec 2016; 10.1098/rsos.160622

̽��ֱ��size of a female animals' brain may determine whether they live longer and have more healthy offspring, according to new research led by the ̽��ֱ�� of Cambridge.

We found that some of the cross-species predictions about brain size held for female red deer, and that none of the predictions were supported in male red deer. This indicates that each sex likely experiences its own set of trade-offs with regard to brain size.

Corina Logan

Alex Thompson

Deer skulls

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Licence type:

Attribution

Smarter than the average bird?

mjg209 — Wed, 15 Jun 2016 08:21:59 +0000

Have humans underestimated the intelligence of birds? A new study suggests one species of bird - the great-tailed grackle - may be able to learn to adapt its behaviour when faced by new challenges.

̽��ֱ��research, published in the Royal Society Open Science journal today, is the first to test the cognitive abilities of great-tailed grackles which are native to the Americas. In Colombia, the great-tailed grackle is the official bird of Cartagena de Indias and many Colombian monuments and artistic works have been created there in honour of its intelligence and adaptability.

Researcher Corina Logan, a Gates Cambridge Scholar who is now a Leverhulme Early Career Research Fellow at the ̽��ֱ�� of Cambridge, has been fascinated by the species for a long time. Before she started her PhD in Experimental Psychology in 2008, she spent time in Costa Rica where she observed the behaviour of great-tailed grackles and was struck by their apparent intelligence.

Dr Logan obtained funding from the National Geographic Society/Waitt Grants Programme and the SAGE Centre for the Study of the Mind at the ̽��ֱ�� of California Santa Barbara in 2012 to set up a field site in Santa Barbara to study cognition in the great-tailed grackle and to do comparative tests with New Caledonian crows. Relatively few studies have been done on this species up until now, and none on their cognitive abilities.

̽��ֱ��research Dr Logan conducted has resulted in three peer-reviewed papers, two of which have now been published. ̽��ֱ��latest, published by the Royal Society Open Science, is out today.

Its focus is the great-tailed grackle’s behavioural flexibility, its ability to learn to adapt to changed circumstances, and whether behaviourally flexible individuals can invent new behaviors to solve novel problems. ̽��ֱ��tests showed they didn’t, which Dr Logan says suggests that behavioural flexibility and innovation do not measure the same thing, contrary to common assumptions. What they could do was adapt their behaviour to attain certain goals.

In two of the tests she conducted, grackles showed they were able to problem solve. One, the colour association task, involved an ability to discriminate between different colours of tubes. A gold and a silver tube were placed on a table at the same time, with one of the tubes containing hidden food. Once birds learned that the food was always in the gold tube, the food was then switched to the silver tube.

All the grackles were able to quickly change their behaviour to primarily choose the silver tube. Most other species were also able to switch colour cues, but the majority took longer to do so.

̽��ֱ��second, more complex challenge, was a problem-solving test called Aesop’s Fable. It involved food floating in a partially filled water tube. ̽��ֱ��birds had to work out that they could raise the water level and bring the food within reach by inserting objects into the tube. All of the grackles solved the problem, but only two changed their preferences in a follow-up test, thus exhibiting behavioural flexibility.

Dr Logan says that the speed at which the grackles solved problems was not a predictor of their behavioural flexibility. Moreover, different grackles seemed more flexible than others on different tasks.

Her third paper which will be out later in the summer will investigate the possible reasons for this.

She is now applying for grants to investigate this variation between grackle populations across their range in North and Central America. She is interested to find out if certain circumstances, such as length of stay in one particular area, how well fed they are or genetics play any part in determining which populations are best able to adapt to new challenges. She is also interested to see if grackles are more flexible in particular contexts. “I want to understand how behavioural flexibility works and why it differs according to the type of problem being solved,” she says.

*See Corina's experiments in action: https://www.youtube.com/watch?v=_PQEaYxw0fw

For an overview of her research, see https://www.youtube.com/watch?v=WtanQqoISCs

Behind the scenes with Tequila: https://www.youtube.com/watch?v=X_Xl8cK5LLk

Corina Logan's research investigates behavioural flexibility in the great-tailed grackle.

I want to understand how behavioural flexibility works and why it differs according to the type of problem being solved.

Corina Logan

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

Yes

Mental time-travel in birds

ns480 — Fri, 14 Oct 2011 08:15:12 +0000

Some tropical birds collect their prey at army ant raids, where massive swarms of ants sweep through the forest and drive out insects. ̽��ֱ��behaviour of interest is called bivouac checking; it allows these birds to track the cyclical raid activity of army ant colonies.

Army ants have regular alternating periods of high and low raiding activity, and birds visit the ants’ temporary nest sites (bivouacs) to determine which colonies are raiding on a given day.

̽��ֱ��new findings published today in the journal Behavioural Ecology, suggest that bivouac checking allows birds to keep track of multiple army ant colonies, keeping account of which colonies are in periods of high-raiding activity while avoiding colonies with low-raiding activity.

Recent research has discovered that birds check army ant bivouacs at the end of the day, after they have fed at the raid. They may use the information about the army ant nest location the next day to find the ants again, thus accessing a past memory (the nest location) to fulfil a future need (bird will be hungry tomorrow), also known as ‘mental time-travel’.

Two of the authors of the study Corina Logan of the ̽��ֱ�� of Cambridge, and Sean O’Donnell of the ̽��ֱ�� of Washington, observed bivouac checking behaviour in Monteverde, Costa Rica.

Mental time-travel consists of two elements: the ability to remember past events and the ability to anticipate and plan for future events. It has traditionally been considered a quality unique to humans. However, ever since Nicola Clayton of the ̽��ֱ�� of Cambridge discovered that scrub jays (a species of large-brained crow) can remember the past and plan for the future, there have been a suite of studies showing evidence of this ability in other species as well. We now know that corvids (birds in the crow family), some primates, and possibly rats have all shown the ability to remember the past and plan for the future.

Corina Logan, said: “We suspect that future planning could be involved in bivouac-checking bird behaviour because the birds were checking bivouacs when they were not hungry, a behaviour that does not make sense until the next morning upon return to the bivouac when the bird finds the ants raiding again and encounters its next meal - a delayed benefit.”

Until recently, it has been difficult to find model systems for studying mental time travel in an ecologically relevant way. “ ̽��ֱ��fact that we might have happened on a whole new system for exploring these capacities is quite exciting,” added Corina Logan.

Certain types of birds may track army ant swarms using sophisticated memory and the ability to plan for the future.

̽��ֱ��fact that we might have happened on a whole new system for exploring these capacities is quite exciting.

Corina Logan

Glenn M Duggan FZS

White Whiskered Puff bird

This work is licensed under a Creative Commons Licence. If you use this content on your site please link back to this page.

Yes