Size matters: preventing large mammal extinction

July 21, 2005

Saving large mammals such as elephants and rhino from extinction could be made more effective by focusing efforts on individual species as well as their habitats.
Scientists at the Zoological Society of London’s Institute of Zoology (IoZ) and Imperial College London have identified fundamental new approaches to improve the success of large mammal conservation. Published today in the journal Science, the largest study of its kind analyses key factors linked to the extinction of mammals.

“Conservation biologists have always known that large bodied mammals are at greater risk of extinction,” comments Professor Georgina Mace of the IoZ, “Now we understand the mechanisms, we are able to tailor conservation programmes dependant on size, to ensure they’re more effective.”

The study showed that extinction risk in smaller mammals, below approximately 3kg (about the weight of a small domestic cat), is determined primarily by the size and locations of their distributions, and the human impact to which they are exposed. Larger mammals have the additional pressure of biological disadvantages such as long gestation period and late weaning age to contend with, significantly increasing their susceptibility to extinction.

“In a world dominated by people, being big is substantially more of a disadvantage than we realised, which implies that the conservation of large mammals should assume a particular urgency,” said Dr Marcel Cardillo of Imperial College London.

“From a conservation policy angle, the message would be: small may be conservable but it is a little trickier for the larger mammals,” commented Dr Andy Purvis of Imperial College London.

The research findings suggest smaller species, of around less than 3kg, would benefit from conservation of their habitat area, whereas, larger bodied animals require a different approach, focusing upon the specific species, their biology and their habitat.

“This understanding enables us to predict what species are most at risk in the future,” said Dr Purvis. “That provides a way for conservationists to go on the front foot rather than wait for accidents to happen. We can try to work out which species are the ones we can do something for, and do some pre-emptive conservation planning. Of course, prevention is always cheaper than cure.”

The research means large bodied mammals such as ungulates (which include rhino and zebra) and many primates are more likely to be predisposed to decline and extinction.

Biological traits such as low population density, slow life history, late weaning age and extended gestation in mammals above a certain size means they are evolutionarily disadvantaged in the face of human impact, compared to species of smaller size. Large mammals may therefore need a more complex conservation strategy, which takes into account their biology in combination with the external threats they face.

Source: Zoological Society of London (ZSL)

Explore further: Weirdly shaped mouse sperm can be used to tell species apart

Related Stories

Weirdly shaped mouse sperm can be used to tell species apart

December 4, 2018

Think back to health class and picture a sperm. It's got a smooth rounded head, with a long skinny tail at the end, right? As it turns out, the sperm from different species of animals have different shapes—and, as a new ...

Recommended for you

Field-responsive mechanical metamaterials (FRMMs)

December 11, 2018

In a recent study published in Science Advances, materials scientists Julie A. Jackson and colleagues presented a new class of materials architecture called field-responsive mechanical metamaterials (FRMM). The FRMMs exhibit ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.