African wild dogs like to breed at the coolest time of year, and climate change has shifted the average timing of birth by 3 weeks in just 30 years
27 June 2022
African wild dogs are giving birth 22 days later than they did 30 years ago due to climate change.
Briana Abrahms at the University of Washington in Seattle and her colleagues analysed data on 60 packs of wild dogs in Botswana covering the period between 1989 and 2020, including the dates when the dogs gave birth each year.
They compared this data to a climate model they created based on information from a nearby weather station. This showed the maximum temperature the dogs experienced each day in that region of Botswana.
African wild dogs like to breed at the coolest times of the year, and this is coming later and later, says Abrahms. In 1990, the average date when they gave birth was 20 May. In 2020, they gave birth 22 days later, on 12 June.
It is unclear why exactly wild dogs like to breed when the temperature is coolest, but it is probably linked with when hunting conditions are optimal, says Abrahms.
“For the first 90 days or so, when a wild dog is born, it is looked after by its mother in a den,” says Abrahms. “It’s safer from other predators and it’s safer from the elements,” she says. During this period the other dogs in the pack must hunt for both the mother and pup.
The team found a close correlation between the shift in birthing dates and increasing temperatures. The maximum daily temperature experienced by the dogs rose by 3.8 degrees in the study period. “It’s a very tight correlation,” she says. “The rate of warming and the rate of shifting breeding – the lines are almost parallel.”
The rise in temperatures may also be affecting pup survival rates. “We’re seeing fewer pups actually emerging from the den,” says Abrahms, though it’s not clear why.
Changes in breeding schedules due to climate change have been seen in many animals, including red squirrels and great tits, but the shift in wild dogs seems unusually dramatic. One study looking at altered animal life cycles found an average shift of 2.88 days per decade.
Wild dogs may have such a big shift because their breeding patterns are exceptionally sensitive to temperature, says Abrahms.
“The results are stark. The shift in the timing of denning behaviour by one week per decade is significant, and only likely to accelerate,” says Julia Myatt at the University of Birmingham in the UK. “Animals are able to adapt and shift their behaviour, but the picture is complex and the rate of change in the environment is so rapid that they may not be able to keep up.
“This study will help to re-focus our efforts on their conservation and the impact of climate change on the ecosystem in which they live.”
Journal reference: PNAS, DOI: 10.1073/pnas.2121667119
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