An online resource based on the award-winning nature guide

Ectothermic

Some Spiders Still Active

10-29-18 march fly and spider_U1A1162Spiders are ectotherms – warmed and cooled by their environment. In the fall, those outdoor species that remain alive through the winter begin preparing themselves by producing antifreeze proteins that allow their tissues to experience below-freezing temperatures. When a small particle of ice first starts to form, the antifreeze proteins bind to it and prevent the water around it from freezing, thus preventing the growth of an ice crystal. Some species survive in temperatures as low as -5 degrees Celsius.

The pictured hammock spider, still active in late October, is nourishing itself by drinking the dissolved innards of a fall-flying March fly, whose name comes from the predominantly springtime flight period of most March Flies (of the 32 species in the genus Bibio in North America, only three fly in fall).

A common belief is that once cold weather appears, outdoor spiders seek shelter inside houses.  In fact, only about 5% of the spiders you find in your house lived outside before coming into your house, according to Seattle’s Burk Museum.  The reason people tend to notice them more inside may be because sexually mature male spiders become more active in the fall, wandering far and wide in search of mates.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.

 

Advertisements

Snapping Turtles Entering Hibernation

10-22-18 snapper IMG_5801Most Snapping Turtles have entered hibernation by late October. To hibernate, they burrow into the debris or mud bottom of ponds or lakes, settle beneath logs, or retreat into muskrat burrows or lodges.  Once a pond is frozen over, how do they breathe with ice preventing them from coming up for air?

Because turtles are ectotherms, or cold-blooded, their body temperature is the same as their surroundings.  The water at the bottom of a pond is usually only a few degrees above freezing.  Fortunately, a cold turtle in cold water/mud has a slow metabolism.  The colder it gets, the slower its metabolism, which means there is less and less of a demand for energy and oxygen as temperatures fall – but there is still some.

When hibernating, Snapping Turtles rely on stored energy.  They acquire oxygen from pond water moving across the surface of their body, which is highly vascularized.  Blood vessels are particularly concentrated near the turtle’s tail, allowing the Snapper to obtain the necessary amount of oxygen to stay alive without using its lungs.

Naturally Curious is supported by donations. If you choose to contribute, you may go to https://naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.


Painted Turtles Basking

3-23-16 painted turtles 033Being an aquatic species, most painted turtles hibernate in the mud at the bottom of ponds. They dig down as far as ten feet where they spend the winter hovering around 43°.  In the spring, when the temperature of the water approaches 60°, painted turtles begin actively foraging, but the first priority upon awakening is to warm up their bodies.  Turtles are ectothermic, or cold-blooded, thus the temperature of their bodies is determined by the  environment that surrounds them.  To be active, painted turtles must maintain an internal temperature of 63°- 73°.  They reach and maintain this temperature by basking in the sun, particularly in the cold, first weeks of spring.  Once warmed up, the turtles will forage, and when they begin to cool off, basking resumes.

Competition for basking sites such as floating logs and rocks can be fierce.  It is not unusual to see many painted turtles lined up on a floating log, or turtles piled one upon the other on a rock in an effort to maximize the effect of the sun’s rays.  The heat they’re obtaining increases their metabolism, aids in digestion and allows males to start producing sperm.  The sun also strengthens their shells and reduces the amount of algae on them, thereby reducing the chances of bacterial or fungal infection.

 Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com  and click on the yellow “donate” button.