Tag: Mammals

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Can herbivores relax?

My how big you are!

and yet your range contracts. Can

herbivores relax?

 

As the human population around the world expands, the impact we have on wildlife increases due in part to more land being used for habitation or agricultural purposes. Large carnivores are particularly vulnerable to anthropogenic threats such as loss of prey base and human-wildlife conflict (often to do with livestock).

Wolf & Ripple (2017) created and analysed large carnivore range maps from present and historical (~AD1500) data. They found that large predators historically occupied 96% of the world’s land area whereas now they occupy 34%. A number of species have suffered an decline in range of over 90%, including the red wolf (99.7%), Ethiopian wolf (99.3%) and the tiger (95.3%). Overall the greatest range contractions occurred in South-eastern Asia and Africa.

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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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How small the harvest

How small the harvest

for sustainability,

this cream-coloured gold.

 

Illegal poaching and the ivory trade have decimated African elephant populations, but could ivory be harvested sustainably at a level to both maintain the species and satisfy the trade?

By modelling a reference population of African elephants, Lusseau & Lee (2016) show that only a very small amount of ivory can be harvested sustainably without endangering the species and that this amount is well below the current demand. They comment that ‘any overexploitation very quickly runs the risk of driving elephants to extinction’.

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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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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).