Climate change affects not just large, cold-adapted animals in the arctic like polar bears, but also the small creatures that live in warmer climates. Numbats (Myrmecobius fasciatus) are small marsupials native to Australia that are greatly affected by the warming temperatures. Numbats are the only marsupials in Australia that are only active during the day when temperatures are at their highest. These adorable squirrel-like animals forage for termites that live in the ground and in rotting logs. Since termites do not provide many calories in their diet, numbats have evolved to conserve body heat that protects them in cooler temperatures. When temperatures exceed 72 degrees, a numbat may spend only about 10 minutes in the sun before overheating, researchers reported in the Journal for Experimental Biology (Cooper and Withers 2024). If temperatures rise above this limit, which often happens with recent rapidly heating global temperatures, a numbat may not have much time to forage during the day at all. Even ducking in the shade during the day is not enough to help keep numbats cool. The research team studying numbat foraging activity, calculated that only 18% of the heat rising a numbat’s internal body temperature, comes from direct sunlight. The high air temperatures and heat trapped in the ground also warm the numbat’s body to its limit. A possible solution that numbat’s may try is limiting their foraging to the early morning or late evening to escape the high temperatures during the day. This may only be viable for a limited amount of time until even these cooler times will become too hot if global temperatures continue to rise, and even before then, this may not be enough time to forage and satisfy the animal’s energy needs. This already endangered animal is struggling with the pressure of predation from cats and foxes is now faced with the threat of climate change like many wildlife species around the world. Further research into how the loss of termite foraging will impact numbat populations is a key next step for the conservation of this species.
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Numbats are built to hold heat, making climate change extra risky for the marsupials
Research Source:
C. E. Cooper and P.C. Withers. Implications of heat exchange for a free-living endangered marsupial determined by non-invasive thermal imaging. Journal of Experimental Biology. Vol. 226, January 7, 2024. doi: 10.1242/jeb.246301.