Darren Naish, in his great post on the origins of the domestic dog, writes:

As a rough rule of thumb, the domesticated forms of wild mammal species (1) revert back to wild-type after being feral for a few generations, and (2) readily interbreed with their wild ancestors. If domestic dogs are wolves, then the many populations of feral dogs that live world-wide should theoretically have reverted back to being wolf-like in appearance and behaviour. But they haven’t. Instead, domestic dogs always end up looking like pariah dogs – the relatively small (11-16 kg), socially flexible semi-domesticated and feral dogs of the Old World tropics.

…

Archaeological data shows that pariah dogs have a stable history, with dog skulls from 4000 year old deposits in Thailand being essentially identical to the modern dingo-like pariah dogs of the area.

A recent post on O&P regarding Heck cattle got me thinking about this point. For those who don’t want to click through, Heck cattle are an attempt to breed back to the extinct ur-cow – the aurochs. The general consensus on Heck cattle seems to be that the attempt was a failure; “once a genetic lineage is gone, it cannot be ‘bred back'”*. My thought on all this is that it seems to show that once genetic material is lost in a population (as a result of domestication) it’s gone – all the king’s horses, etc. Perhaps, then, it’s not shocking that dogs revert to pariah dogs in some number of generations – the genes that would allow reversion to a more wolfy form are just gone from the domesticated dog’s gene pool. To extend the title of the post a bit – border collies are to pariah dogs as Holsteins are to criollos/Texas longhorns? Don’t get me wrong – there are a number of other persuasive points in Darren’s post – I’m just not sure about the ‘won’t revert to wolves’ argument at this point.

Migratory birds are heading north – the dogs and I flushed a small group of mallards this morning from a vernal pool (vernal lake is more like it) across the street. Two interesting bits of songbird migration info have come over the transom in the past couple days. First, check out this excellent post on songbirds, coffee and the World Bank from the Terrierman (I’m sure many of my visitors also check Patrick’s blog, but if you don’t here’s a reason why you should). Second – via NPR on the drive in this morning – greater noctule bats (Nyctalus lasiopterus) are occupying an unexpected niche – preying on migrating birds as they come north through Europe.

The ability of giant noctules to prey on the wing upon nocturnally migrating passerines appears unique not only among bats but also within the whole animal kingdom. Although carnivorous bats feeding on small-sized vertebrates are not rare, they all live in the Tropics and collect their prey from substrates. The few species of falcons which capture migratory birds along the Mediterranean and African coasts are exclusively diurnal. Finally, owls, as typical night-active predators, never forage in the open space: moving prey is detected from substrates through passive-listening of rustling noises. *

Here’s a link to the paper that is causing the hubbub – right now it looks like the Public Library of Science servers are getting slammed, but when they come back up I’ll likely post an addendum.

From: Figure 1 of Popa-Lisseanu, A. G., Delgado-Huertas, A., Forero, M. G., Rodriguez, A., Arlettaz, R. & Ibanez, C. 2007. Bats’ conquest of a formidable foraging niche: the myriads of nocturnally migrating songbirds. PLoS ONE 2(2): e205.