In the farming village of Colola, Mexico, many families have dogs that help guard the house and fields. But these canine companions also wreak havoc on the nests of threatened sea turtles at a nearby beach, gobbling up eggs as a way to compensate for a lack of food at home.

There are roughly 700 million dogs around the world, and about 80 percent of them are village dogs that aren’t confined to houses or yards. Left to fend for themselves, these dogs often prey on wild animals such as reptiles. At some beaches, more than half of the sea turtle nests have been plundered by dogs.

In a recent study, researchers focused on the problem of nest scavenging at Colola Sanctuary, Mexico, where eastern Pacific green turtles, olive ridley turtles, and leatherback turtles lay eggs. The team tracked the movements of 19 dogs with radio-collars and observed their behaviour on the beach. The researchers also asked the owners how much they fed their dogs, then calculated the metabolic energy per kilogram of body weight that each dog received from its daily meals of corn tortillas.

Nine of the dogs raided sea turtle nests, the researchers report in Animal Conservation. Dogs that ate turtle eggs got about 36 percent less metabolic energy per kilogram of body weight from their corn tortillas than the dogs that didn’t eat eggs, suggesting that the nest scavengers weren’t getting enough food at home. And 39 percent of the owners had fed their dogs turtle eggs or egg shells, perhaps giving their pets an early taste for this protein-rich snack.

Since the dogs visited the beach mainly during the cooler night and early morning hours, owners could protect sea turtle nests by confining their animals from 9 PM to 6 AM, the team suggests. And giving the dogs bigger meals could keep them satisfied enough to leave the turtle eggs alone. — Roberta Kwok | 17 July 2014

Source: Ruiz-Izaguirre, E. et al. 2014. Roaming characteristics and feeding practices of village dogs scavenging sea-turtle nests. Animal Conservation doi: 10.1111/acv.12143.

Image © Jarno Gonzalez Zarraonandia | Shutterstock