We've often been told that only birds and mammals are warm-blooded. As with so many things in the biological world, though, generalizations frequently have exceptions. Even the tuna fish has a degree of warm-bloodedness. Closer to home, the group of moths—the hawk moths—that include the tomato worm is kinda, but not quite, warm-blooded.
Many insects become inactive in cooler weather, unable to make muscles
react fast enough to maintain flight. The moths in question though, are able to forage
for nectar even when the temperature drops down nearly to 40 degrees, a temperature
that tends to send many insects into slow motion. We all know that shivering creates
heat, and shivering is what the hawk moths do to warm up cold flight muscles before
taking off. Once in flight, the rapid burning of fuel by the flight muscles together
with heat-regulating systems keeps them at a comfortable 86 or so degrees. Of course,
burning fuel that fast means they had jolly well better find that nectar if they're
going to be around to shiver and fly another day! 
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.<