Prior to new research, it was generally thought sufficient space in which to roam and avoid lions was enough for the endangered wild dog to thrive. However, a study into their dynamics, conducted in the Hluhluwe-iMfolozi Park in KwaZulu-Natal, has revealed a number of factors influence their success.
In a first of its kind study in South Africa spanning almost 30 years, researchers found that the size of the pack, population density, age of the females, and the amount of food available all affected the age when females first had a litter, the size of the litter and pup survival.
“Wild dog reproduction is well studied across a range of ecosystems, but our study provides the only account of factors affecting females’ age at first litter,” says David Marneweck, PhD candidate at the University of Pretoria’s Mammal Research Institute. Marneweck is also the chairperson of the Wild Dog Advisory Group of South Africa.
Wild dog packs generally consist of an alpha female and an alpha male with subordinate non-breeding helpers. Packs spend approximately three months a year raising a litter of pups in the den. However, subordinate and yearling members of the pack regurgitate food for pups more often than dominants and adults, so the survival of these dogs is important for the dynamics of the pack.
Older females are also most likely better at selecting safe den sites. “We found pup survival to be enhanced when older breeding females were part of larger packs,” Marneweck explains. “This effect was particularly strong for pup survival to six months.”
A study carried out in the Kruger National Park indicated that a lack of rainfall resulted in the survival of more pups, but Marneweck and his team did not find this to be a factor in Hluhluwe-iMfolozi. “We tested rainfall and found that it did not play an important role in influencing pup survival. Rather, we found that older females in larger packs raised more pups, suggesting that wild dog social dynamics more than surrounding ecological conditions affected the survival of pups,” he adds.
The biggest surprise of the study indicates females start breeding younger when more food is available. Sometimes this can be as much as 1–2 years earlier than females from other packs. On average, a wild dog has her first litter at between 3–3.5 years old.
During the study period, they found four instances of breeding by a subordinate female in the pack. According to literature, most often only the alpha female in the pack breeds. “This suggests that wild
dogs might be more promiscuous in their packs than commonly thought,” Marneweck says.
Researchers compiled detailed life histories for each wild dog spanning the period June 1993 to June 2016. Wild dogs are easily identifiable from their coat patterns, which help record individuals and group size, as well as age and sex breakdown, pregnancies, and dominance status of individuals. Births and denning status were also captured on a weekly basis. Twenty-two wild dogs were introduced into Hluhluwe-iMfolozi in 1980. Numbers fluctuated until 1996, but increased to 68 at the start of the 2016 denning season.
Marneweck says the study shows that although wild dogs are endangered, if there is lots of food in an area, then they can breed quickly, have pups and recruit more individuals into the population.
“Without understanding reproduction, it is very challenging to understand what conditions might favour a population to increase or decrease,” he adds. “As many conservation programmes target population increase as a measure of success and effective conservation, studies like this that highlight what influences reproduction give critical information for this endangered carnivore.”
Written by: René de Klerk
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