Wolf family values

Wolves' social structure affected by hunting

source: Sharon Levy
New Scientist vol 206 no 2764, 12th June 2010  
starts p40, four pages long

Gordon Haber, who died in 2009, was an independent biologist whose findings on the effects of hunting on wolf social structure in Alaska are now backed by researchers elsewhere. Alaskan wolves have been killed and sterlised, affecting as many as 50% annually. Population size has remained stable, but extended families have been broken up by killing, which may mean that younger wolves can no longer learn from experienced oldsters. Less experienced survivors are more unpredictable, and kill more large prey per wolf, so hunting wolves can be counter-productive.

Haber's findings are backed by studies from Yellowstone, where wolves have been reintroduced and are protected. Yellowstone  wolves live longer, sometimes to over 10 years old, and sometimes stay with packs until they are five years old. Elsewhere, wolves rarely survive to over three or four years old. Yellowstone packs are also larger, around 11 wolves, and some packs have more than 20 members, while elsewhere packs tend to have five to six members. Yellowstone packs have developed a division of labour, with females rushing elk and selecting weaker prey, and males killing the prey. Selecting elk is a skill that peaks at three years old, while taking down elk peaks at two years old. Younger wolves learn from observation and experience. Larger packs can eat all their kill, while smaller packs have to leave some, eaten by scavengers, and smaller packs thus kill more large prey per wolf.

These findings are echoed by studies in Ontario, Canada, where wolves have been protected in Algonquin Park since 2001. Population size has remained steady, but the wolves are now setting  up family groups, rather than packs with unrelated members. Packs are also now taking moose, larger than deer, previously the main food source. This means that youngsters are learning new skills. Limits on elk numbers can boost the diversity of songbirds and plants.

Haber emphasises wolves' sociality, a trait also found in howler monkeys. Female howlers raise more young if they live with close kin. African elephants hit by poaching deaths suffer family disruption, with young males becoming more dangerous.

Buffer zones outside parks can help wolf families survive, but they are being removed. In march 2010, wolf trapping was permitted outside denali Park, Alaska, and in 2009, Idaho and montana allowed wolf hunting around yellowstone. This has already led to the deaths of the alpha male and female from one pack, and the survivors' fate is unknown.