Lizards Pant to Keep Cool

INSIDE JEB

Lizards pant to keep cool

of the reptiles’ natural habitats with the temperature at which they began panting, the species from cooler locations resorted to panting at lower temperatures than the animals from hotter climes.

However, three species – Yarrow’s spiny lizard (Sceloporus jarrovii), crevice spiny lizard (Sceloporus poinsettii) and the Chihuahuan spotted whiptail (Aspidoscelis exsanguis) – gained little or no benefit from panting. The scientists also noticed that the smaller members of a species tended to hold off panting until higher temperatures, which they suspect could be due to the smaller reserves of water carried by dinkier animals. In addition, the duo checked to see whether panting could be the first warning that a lizard is in peril from the heat, but when An eastern collared lizard (Crotaphytus collaris). Photo credit: Caleb Loughran. they analysed the pattern it was clear some lizards were still in a good state, while It’s a common misnomer that lizards are locations ranging from baking deserts to others were near to collapse. In short, cold blooded. They are anything but and cooler locations high in the Manzano panting is not a reliable symptom that an also run the risk of overheating when mountains. ‘Aspidoscelis are often overheated lizard may be getting into temperatures rocket, just like many other difficult to capture because they are trouble. creatures. ‘The most common way lizards almost always moving and slide right control their body temperature is by through the lasso that we use to catch Having confirmed that lizards can resort moving back and forth from sunny to them’, laughs Loughran. Then, the duo to panting when the temperatures rocket shaded sites’, says Caleb Loughran from settled each lizard into a plastic chamber and are, in many cases, capable of the University of New Mexico, USA, to film the reptiles and capture whether slowing their body temperature rise, explaining that many species seek shade they began panting, as they gradually Loughran and Wolf point out that the or strike cooling poses to keep their increased the air temperature from 35°C cooling strategy is only practical when temperatures down. But Loughran and to near 50°C over a 4 h period. In addition, there is sufficient water on hand. ‘A hotter Blair Wolf, also from the University of the scientists measured the reptile’s body environment means using more water to New Mexico, wondered whether some temperature to track whether panting gave stay cool or being less active, both of lizards may also resort to a strategy used the animals any relief from the spiralling which may increase extinction risk in a by over-heating dogs and birds to keep temperatures. rapidly warming climate’, says Wolf. cool: panting. ‘Cooling down by Keeping their body temperatures down by evaporating water by panting might prove Impressively, all of the lizards began panting could give some species the edge to be an important alternative to moving panting at body temperatures above over others residing in the same locations from a hotter to cooler environment when 36.8°C, although 9 species only resorted when climate change really begins to take overheating is a risk’, says Wolf. to this technique for cooling at its toll. temperatures above 40°C. And when 10.1242/jeb.235036 Setting out in search of lizards ranging Loughran and Wolf tracked the lizard’s from sizeable chuckwallas (Sauromalus body temperature after they began Loughran, C. L. and Wolf, B. O. (2020). The functional significance of panting as a mechanism ater) and medium-sized eastern collared panting, the duo could see that 14 species of thermoregulation and its relationship to the lizards (Crotaphytus collaris) to tiny side- were able to reduce their body critical thermal maxima in lizards. J. Exp. Biol. blotched lizards (Uta stansburiana), temperature by up to 4.8°C, with the 223, jeb224139. doi:10.1242/jeb.224139 Loughran and Wolf collected more than average lizard cooling by 2.7°C. Also, Kathryn Knight 260 lizards from 17 species residing in when the team compared the temperature [email protected]

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