How the deer mouse evolved its burrow

[Oolon Colluphid]

Deer mice

http://upload.wikimedia.org/wikipedia/commons/8/8a/Peromyscus_maniculatus.jpg

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Animal Behaviour, Volume 77, Issue 3, March 2009, Pages 603-609

The evolution of burrowing behaviour in deer mice (genus Peromyscus)

Weber and Hoekstra

The evolutionary history of most behaviours remains unknown. Here, we assay burrowing behaviour of seven species of deer mice in standardized environments to determine how burrowing evolved in this genus (Peromyscus).

We found that several, but not all, species burrow even after many generations of captive breeding. Specifically, there were significant and repeatable differences in both the frequency of burrowing and burrow shape between species. Moreover, these observed species-specific behaviours resemble those reported in wild mice.

These results suggest that there is probably a strong genetic component to burrowing in deer mice.

We also generated a phylogeny for these seven species using characters from four mtDNA and two autosomal loci. Mapping burrowing behaviour onto this phylogeny suggests a sequence for how complex burrowing evolves: from small, simple burrows to long, multitunnel burrows with defined entrance and escape tunnels. In particular, the most ‘complex’ burrows of P. polionotus appear to be derived.

These behavioural data, when examined in a phylogenetic context, show that even closely related species differ in their burrowing behaviours and that the most complex burrows probably evolved by the gradual accumulation of genetic change over time.

[DMB]

It's always a little bit hard for me to take on board how much behaviour is genetically controlled. Of course, if you really think about it, it has to be so, but it's something we're keen to deny happening in ourselves.

[lpetrich]

Instinct does get mixed up with learning in difficult-to-disentangle ways, however.

Mother rats will normally lick their pups, but if one raises some rats with collars that keep them from licking themselves, they will not lick their pups.

And to take an example from our species, some people seriously speculate about a "language instinct", but one has to learn whatever languages that one uses, and only a tiny fraction of their vocabularies is directly related to what they describe. We don't call dogs woof-woofs, for instance.

[Oolon Colluphid]

On the language thing, see, of course, Steven Pinker. The idea is that learning a language is a genetically hard-wired instinct, but what language that is varies with the environment -- and includes sign languages.