Wolf Pack Dynamics (Preliminaries) Virginia Stoll Wm. D. Stone

A Mexican Lobo

The ‘Lobo’ Smallest subspecies of North American Gray Wolf 50 – 80 pounds ~30 inches at the shoulder Original range much of Mexico, NM, AZ

History Almost extinct by mid-20 th century Listed as endangered 1976 Recovery effort started 1977 Small population captured in Mexico Two small captive populations 7 founders.

Wolf Packs Basic unit of population – the pack –One alpha pair Normally the only breeders –Young adults Help hunt and baby-sit –Pups

Formation of new packs Young adults can leave the pack – become ‘lone wolves’ New packs can be formed by a pair of lone wolves joining up Very large packs can split Death of one of the alpha pair can cause pack to split

Pack size Prey –Size Mostly elk –Availability Lots of elk Scavengers –Ravens Can eat 2 lbs. of meat per day each

Population Pressures In the New Mexico re-established wolf population, two largest sources of adult mortality are –Cars –Illegal shooting

Natural Mortality Food pressure mostly affects survival of pups to weaning Inter-pack battles can be a significant cause of death

Genetics Starting with tracking one locus, with one marked gene in a single individual Probability of duplicate copies in an individual (comparative only)

Input from Federal Wolf Biologists New Mexico packs rarely are larger than a breeding pair plus pups –Subspecies difference? –Growth stage vs. steady state? So far, little food or territory pressure

Genetics US Fish & Wildlife has full genetic profiles of every wolf they have handled Very small number of founders Selective breeding for genetic diversity They hope our model can help

Model Results

Female with pups