Tag: Behaviour

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A zoo without bars by Dr Lisa Holmes

A zoo without bars –

Building thoughtful habitats

for all to explore.

Chester Zoo (www.chesterzoo.org) is a registered conservation and education charity that supports projects around the world and closer to home in Cheshire. Welcoming 1.9 million visitors a year, it is the most visited zoo in the UK; home to over 15,000 animals and more than 500 different species, many of which are endangered in the wild.

Chester Zoo has continued with the ‘always building’ philosophy of our founder, George Mottershead, who created the UK’s first zoo without bars and focused on animal wellbeing and conservation. In 2015 Chester Zoo opened Islands which was the largest zoological development in the UK to date. The Islands expedition is an immersive experience, taking visitors through six South East Asian islands to discover the incredible wildlife native to those areas and highlight the conservation issues that the zoo staff are working hard to address.

Modern day zoo research encompasses many aspects of biological and social sciences with the overall aim to address challenges faced in the natural world. Chester Zoo not only supports conservation research both in- and ex-situ but leads on important projects both in the UK and across the globe to improve the management of animals and plants, influence sustainability of wild populations and inspire others to Act for Wildlife.

Lisa Holmes is the Behaviour and Welfare Scientist within the Applied Science team at Chester Zoo. Her role involves working closely with the animal curators and keepers to provide evidence-based recommendations to enhance animal wellbeing and help to inform enclosure design. Lisa supervises postgraduate and sandwich placement students who help to gather key data for a wide range of species. Lisa’s research team are currently working on a long-term project assessing the response of species which have moved into the new Islands habitats.

Check out Lisa’s latest sciku ‘The Masterplan’ here.

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Swim in step

‘Let’s stick together,’

said the guppy to her friend,

‘we can swim in step.’

 

Shoaling in fish can provide safety from predators and increase the effectiveness of group movement. This group efficiency can be influenced by the behaviour of individuals within the group and a measure of group coordination is the extent to which animals align with one another – termed polarisation.

Investigating female guppies, Davis et al (2017) found that groups of familiar individuals were more polarised than groups of unfamiliar individuals. This was especially apparent when the groups were in novel surroundings and reduced with habituation to their surroundings. This increased coordination suggests that groups of individuals familiar with one another may be better able to cope with challenging situations.

Original research: https://doi.org/10.1098/rsos.170312

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Cause and effect

They’ll blow your house down

as they grasp cause and effect

much better than dogs.

 

The process of domestication is thought to impact on a number of cognitive and physical properties as species adapt to the human environment. The close social ties between humans and dogs are an extreme example and comparing the cognition of dogs with wolves can reveal information about the impact of domestication.

Using animals housed under similar pack conditions and with prior experience of interacting with humans, Lampe et al (2017) found that whilst wolves and dogs can follow human-given communication equally well, wolves were better at understanding causal cues in the absence of humans (such as a rattling container indicating the presence of food). Domestication may have led to a reduction in the ability of dogs to solve some problems independently of humans.

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The kids help out

Staying at home, the

kids help out. Breeding becomes

cooperative.

 

In cooperatively breeding species individuals help to raise offspring that are not their own, but how did this costly behaviour evolve? By comparing 3,005 species using phylogenetic analyses Griesser et al (2017) suggest that cooperative breeding in birds occurred in two stages.

First, families formed by the prolonging of parent-offspring associations, with chicks not leaving the nest when nutritionally independent. This appears to have occurred in productive environments where the cost of the offspring remaining at home for longer is less.

Second, the offspring remaining at the home nest then start to help out. In contrast to the formation of family units, the researchers suggest that this happened in more variable environments where the retained helpers can buffer in harsh years.

This theory helps to explain the geographic distribution of cooperatively breeding bird species too – areas where these species are found have often experienced historical declines in productivity. The pre-decline environment may have fostered family formation whilst the decline may have then resulted in the step to cooperative breeding.

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Just nicker!

Don’t make yourself hoarse

in anticipation of

good times, just nicker!

 

Vocal communication is an important element of behavioural interactions within many social species.  Przewalski’s horses produced more whinnies and squeals in response to negative contexts (agonistic interaction, social separation), but more nickers in positive contexts (anticipation of food or affiliative interactions).

Przewalski’s horses are the closest living relative of domestic horses and a comparison between the species revealed both similarities and intriguing differences in their vocalisations, suggesting that the expression of emotional valence (positive or negative) might be species specific as opposed to conserved across species. Maigrot et al, 2017.

Being able to understand vocal expression of animals could lead to the increased welfare of captive species and a better understanding of animal interactions and group behaviour, which in turn might help to aid population management or conservation in endangered species.

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Pray, are you a predator?

Have we met before?

Pray, are you a predator?

I am so naive!

 

Predators are a threat for most animals and gauging whether a novel species is dangerous or not can be a life or death judgment. Whilst some species may have a degree of innate predator recognition, research suggests other species require prior experience of the predator to learn of its danger.

Great and blue tits were tested with novel and familiar predators. Tits from populations familiar with both sparrowhawks and little owls reacted towards the stimuli as expected, mobbing the predators equally. But tits from populations only familiar with sparrowhawks did not treat the little owl stimulus as a threat, suggesting it wasn’t recognised as a predator. Prior experience of predator species is therefore important in great and blue tits. Carlson et al, 2017.

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Clawed frogs indicate

Clawed frogs indicate

by action and reaction

a choice between shades.

 

Ensuring the welfare of animals used for research is vital both from an ethical stand point and for the quality of the research produced – animals in poor condition do not produce accurate or reliable results. The African clawed frog is a common research species found in laboratories around the world but little work has investigated how to optimally house it in captivity.

Holmes et al (2016) found that a black tank background produced lower levels of ‘stress’ hormone (corticosterone), lower amounts of stereotypical behaviour and a smaller loss in body mass than a white tank background.

As African clawed frogs are naturally dark green/brown in colour and use camouflage to avoid predation, a light background might be more stressful for the frogs as they may appear more exposed. Providing dark tank backgrounds could therefore be an easy method for improving the welfare of thousands of African clawed frogs housed in captivity around the world.

Interested in African clawed frogs? Check out these other Xenopus sciku: ‘Fungal culprit‘, ‘Have frog, will travel‘, ‘Xenopus enrichment‘ and ‘Reservoir or predator‘.

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Plenty of fish

Plenty of fish yet

male voles choose monogamy

… but do their partners?

 

Monogamy is relatively rare in the animal kingdom, with extra-pairs matings happening a lot more than you might think. Males in particular are thought to gain the most from polygamy by being able to sire multiple offspring, whilst females may gain from monogamy through defence or paternal care of their young.

Yet despite having access to multiple females, male prairie voles choose to form exclusive pair bonds with individual females (Blocker & Ophir, 2016). In contrast,  female prairie voles readily engage in promiscuous mating (Wolff et al, 2002).

So why (under laboratory settings) are male prairie voles monogamous whilst females are promiscuous?

Blocker & Ophir, 2016 argue that one explanation could be that the costs to males of trying to hang on to multiple females at once are too great, and that male prairie voles gain the most by aggressively monopolising just one female. Females on the other hand have nothing to lose from polygamy so will mate with other males if the opportunity presents itself.

In prairie voles it seems that monogamous behaviour may be male-driven.

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Bumblebee football

Bumblebee football:

Learning to score for sugar,

self-improvement – Goal!

 

Tool use is an indication of cognitive complexity and has been demonstrated in a number of species, including among primates, marine mammals and birds. Bumblebees trained to manipulate a ball to gain a reward were able to improve on their performance by taking shorter routes and moving the closest ball when presented with multiple balls. The bees were also able to learn socially by watching other bees solving the task. Together this shows a degree of cognitive flexibility that has not previously been recognised in an insect. Loukola et al, 2017.

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Snail shepherds

Cichlid snail shepherds

help their fry play masquerade

…if the crowd’s willing.

 

Keeping your children safe is one of the most important things you can do as a parent. Cichlid fish have young that have striped patterns similar to a species of snail that sometimes lives in the same area – a form of masquerade camouflage protection. The fry only have these patterns in populations where the species of snail is present, and the cichlid parents further help their young by removing other species to snail from their territory, helping to drive up the proportions of striped snails and so increase their offspring’s charade. Satoh et al, 2017.

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Crafty little goats

Crafty little goats –

watching humans solve problems.

See, they learn faster!

 

Many animals can learn how to solve tasks by watching how members of their own species solve the problem. Learning by observing other species is less common and few species have been shown to learn from watching humans. Goats struggle to learn how to solve a detour task (navigating around a ‘V’ shaped hurdle) by themselves but observing a human solve the task just once enables goats are able to solve the task much faster. Nawroth et al, 2016.

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Foundress

Paper foundress queens

Influence their colony

In character and size.

 

We often look for similarities between ourselves and our parents/children, in the way we look or behave. In paper wasps the personality of the queen influences the size and aggressiveness of the colony they found: Bolder queens tend to produce more workers that as a colony are less likely to attack a simulated agonistic stimulus, however whilst shyer queens tend to produce a more aggressive colony with fewer workers. Wright et al, 2017.

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Just a warm up

Oh how sweet dawn’s song!

Yet this choral crescendo

is just a warm up.

 

Many of us enjoying waking up to the sound of birdsong. But whilst we might enjoy the various trills and tweets as the sun rises, the Adelaide’s warbler’s song actually improves over the course of the morning. To appreciate the best of its voice, perhaps the early bird doesn’t catch the worm! Schraft et al, 2017.

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Paternal spider

Paternal spider

to die at the ‘little death’,

worthy sacrifice.

 

Mating is a dangerous game for males of many species of spider, with females often winding up with a nutritional meal to help fuel egg production. Taking their paternal responsibilities to an extreme, male dark fishing spiders spontaneously die during copulation. Females that are allowed to eat their dead mates produce a greater number of offspring, of a greater size and with an increased survivorship compared to females prevented from eating their mate or females provided with an equivalently sized cricket. It seems cannibalism isn’t all bad. Schwartz et al, 2016.

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Enemy within

Enemy within:

Trojan tapeworms plotting for

reckless behaviour.

 

Sticklebacks infected with a tapeworm behave in ways that appear to maximise the tapeworm’s transmission to a new host: swimming near the surface of the water and so increasing the risk of being eaten by birds. A study by Talarico et al (2017) suggests that this change in behaviour is down to the influence of the tapeworm itself rather than a “general, systematic impairment of infected sticklebacks”, although other recent studies have demonstrated that there may also be additional reasons for this behavioural change.

Original research: https://doi.org/10.1007/s00265-017-2265-9

Discussion of study: https://doi.org/10.1007/s00265-017-2272-x

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Immigrant crabs

Immigrant tree crabs

Move from mangrove to salt marsh

…but it’s not the same.

 

Mangrove tree crabs have responded to climate change by moving northwards into a novel habitat: salt marsh. The crabs used to show site fidelity in their historic habitat but the faecal cues they used for this are now often washed away in the salt marsh which is regularly flooded. Climate change may therefore be indirectly affecting foraging behaviour and predation risk. Cannizzo & Griffen, 2016.

Original research: https://doi.org/10.1016/j.anbehav.2016.08.025

 

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Fight, flight or pee

To fight, flight or pee?

That is the question for the

Aggressive cichlid.

 

Aggressive interactions between individuals can be dangerous and energetically expensive and it is important that the two competitors are able to communicate effectively to avoid such costs. When competing cichlid fish engage in agonistic interactions they are known to communicate via visual cues, but new findings suggest they also use chemical cues by urinating during encounters. Bayani et al, 2017.

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Gregarious sharks

Gregarious sharks:

Cohabiting siblings and

multiple lovers

 

Whilst the bluntnose sixgill shark is a widely known species of shark, little is known about its biology. A genetic study looking at polymorphic microsatellites revealed that individuals sampled at the same time and place were often siblings, whilst one female was found to have had up to 9 males fathering her offspring. Larson et al, 2011.

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Road-safety

Road-safety crucial:

Engine noises distract from

predator odours.

 

Noise pollution can have a number of effects on wild animals. Morris-Drake et al (2016) found that road noises meant that dwarf mongooses were slower to detect a predator odour and did not increase vigilance in response to the odour (whilst mongooses exposed to normal ambient noise found the odour faster and showed increased vigilance).

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Lugging worker

Lugging worker ants

use a celestial compass.

Is this a moonwalk?

 

Ants often need to walk backwards when dragging heavy food items to their nests, but how do they navigate when moving in reverse? Rather than relying on visual memories of terrestrial cues, ants instead use their celestial compass – this can be disrupted by presenting ants with a mirror image of the sun’s position in the sky. Schwarz et al, 2017.

Original research: https://doi.org/10.1016/j.cub.2016.12.019

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When courting

When courting with song

do take turns with your neighbour –

Gentlemen hermits!

 

Male long-billed hermits (a sub-group of humming birds) form leks to attract mates by singing, but competing birds close together could overlap singing and confuse each other’s song. To counter this, males close together coordinate to alternate singing bouts whilst males further away from each other (and not at danger from vocal obscuration) overlap their songs. Araya-Salas et al, 2017.