Questions and Answers: In-Depth Responses

I just read a 2003 article from your group by Frederic Leblanc in which it was briefly suggested that L. lutra is able to climb trees. Would anyone be able to verify this for me? Are otters able to ascend vertical tree trunks using their claws, or can they only walk up leaning trees and so forth? Thank you for your time!

Christopher Cox, 22 June 2008

There hasn't been as yet any systematic investigation of the climbing ability of otters, but I do work with zoos, and escape attempts have shown that otters are really quite good at climbing.

The ability of Lutra lutra to climb a vertical tree appears to depend on three things:

1. The diameter of the trunk - if the otter can get its paws most of the way round the trunk, it will hug its way up mainly using muscular power, but anchoring itself with its claws. Otters can't climb a blank surface or a wide trunk.
2. The distance to be ascended - I have not heard of them going up vertically more than about six feet, but an otter bent on escape would not need to go higher than the first branch or the height of the fence
3. The determination of the otter - a really determined otter would keep on going - they do not tire easily and are very strong for their size

Because of paw webbing, Lutra does not seem to be as able a climber as Aonyx cinereus which has the advantage of small strong dextrous fingers (I know one Aonyx that routinely climbs twelve feet vertically up mesh fencing, then paw over paw across the wire roof to reach a small gap in the fence to the pen next door). However, being a bigger otter, Lutra can reach further. Otters can also jump vertically quite high, and most otters I have seen climbing begin with a bounce upward.

Zoo observations also show that wire netting needs to be fairly small mesh (less than 2 inches) in order to prevent Lutra from climbing out, and topped with an solid horizontal overhang inward of at least a foot and a half. This can be augmented with a hot wire. Having said this, however, I know a particular male Lutra that still escapes despite all of this.

They are good at climbing sloping trees!