How to Beat the Summer Heat in Bidwell Park
By Jon Aull
With temperatures now reaching over a hundred degrees in Chico daily, it’s hard on people who love to spend time outdoors but don’t love the heat. Although the official temperature today is only 105 in the shade, I feel this doesn’t tell the whole story, so I’ve taken to the unscientific method of placing a meat thermometer on the picnic table on my deck to measure the “true” temperature (it now reads 140). So I thought I’d look for advice from the native animals of Bidwell Park on coping with the heat, since they have been dealing with this problem for thousands of years and have developed various adaptations to deal with this problem. Here are some of their suggestions.
Aestivation is similar to hibernation, but is a dormancy that takes place in the hot, dry months rather than the cold months. Some local amphibians use this method to keep from drying out in the scorching sun and to avoid the deadly ultraviolet rays. Salamanders, like the California Slender Salamander, retreat underground to gopher holes for this summer shutdown. Western Spadefoot Toads spend an incredible 8-10 months of the year underground, living off of fat reserves.
Our friends the Western Rattlesnakes are conspicuous in spring when temperatures rise, and in late fall, but they are mostly active at night, as is evident by their vertical eye slits, a sign of a nocturnal snake. They also sense their prey through infrared heat sensing pits in front of their eyes, which work better in cooler temperatures. In Chico, the dry air doesn’t retain the heat, so we can get a daily temperature fluctuation of over 35 degrees. So even when the day is too hot for rattlesnakes, it can be quite nice at 4 AM.
As one of the oldest animal species on earth, the Vernal Pool Tadpole Shrimp offer one strategy for survival. These “living fossils” take advantage of the seasonal wetlands of Bidwell Park that fill up every winter and create small islands of rare habitat. When it gets hot and the pools dry up in the spring, the shrimp die, which is probably not the most attractive option for escaping the heat. But they (like the Vernal Pool Fairy Shrimp) do lay a type of egg called a cyst, which contains a fully developed embryo. These lie dormant in the soil, waiting for the next good rain to awaken them from their mummified state. Until enough rain comes, they can “live” in the mummified state for a hundred or more years.
Big Chico Creek is thriving animal habitat. People have taken the cue from aquatic animals and converge on the creek in hot months. Turtles are another survivor from the days of the dinosaurs, and our Western Pond Turtle’s strategy of thermo-regulating, alternately basking and swimming, is one that many have taken to heart. It’s a good day to be a turtle.