Critters of North Idaho: Signal Crayfish
This autumn, a male crustacean will make his way along the river bottom. His twitching antennae will help him pick up the scent of his quarry. Getting close, we’ll realize that this creature isn’t hunting for food; he’s in the mood for love. His quarry is a female of his own species. She has released a special chemical into the water, called pheromones, that produce a scent that draws in the guys from miles around. After initial introductions, the two crustaceans will mate and produce hundreds of young crawfish in their own likeness.
Crawdads, Craydids, Freshwater lobsters, Yabbies or Mudbags. My Dad likes to call them imposter lobsters. What you call these critters largely depends on where you live. Here in North Idaho, many people like to call them crawdaddies or crayfish. These creatures are quite ancient. Fossils of them and their burrows have been found with the ancient bones of dinosaurs! Unlike the dinosaurs, there are several species chilling in the lakes, ponds, streams and rivers of the Pacific Northwest. Today, we will narrow our focus to the signal crayfish (Pacifastacus leniusculus).
Despite that bright-red coloration they’re known for, they actually don’t turn that color until they’re cooked. A healthy, living crayfish is typically reddish-brown or bluish-brown in color, which is much more suitable for camouflage!
Don’t confuse these guys for their marine cousin, the lobster. Both are crustaceans with massive pincers, a tail fin at the base of their abdomen and long antennae. Another similarity they share is that they have a total of eight legs, split into two sets. The front half are longer and used for walking. The back half, called swimmerets, are much smaller.
Can you guess what a crayfish might use swimmerets for? A major difference between crayfish and lobsters is where they live. Lobsters like to live in saltwater, while crayfish live in freshwater.
Let us return to the signal crawfish we met earlier on, shall we? After the male and female part ways, the mother-to-be will find a sheltered place on the riverbed to await the coming eggs. By the time she is finished, she may be carrying anywhere from 200 to 400 eggs under her tail. During their 166- to 280-days-long incubation, the mother will clean the eggs and discard any that are diseased.
The offspring finally hatch in the spring. Even still, the mother does not abandon them. After hatching, the baby crayfish will spend much of its time clinging to its mother’s swimmerets until molting two times. Until then, they venture only a short distance away to practice foraging before hurrying back to their mother at the first sign of danger. The mother is very protective of her brood until they leave to fend for themselves.
Life can be difficult for a young crawfish as they attempt to find food and stay clear of predators. These crustaceans are omnivores, commonly eating water insects and plants. Meanwhile, they often end up on the menu of raccoons, turtles, snakes, water shrews, foxes, those pesky humans and even larger crawfish. This makes life very dangerous for young crawfish, and many do not survive. Those that do often grow about 3 or 4 inches long, and can live to the ripe old age of 16.
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