Land crab invasion alert: Dan Skowronski in Port St. Lucie, Florida said heavy rains this week caused land crabs in the area to evacuate their burrows. His video shows hundreds of the animals climbed onto his backyard porch screen in an apparent attempt to stay out of the water. The crabs are seen climbing up an outside screen as well as scuttling across his yard.
Dan says in the video that this happens sometimes once per year.
Land crabs cause holes in people’s laws when they dig down just to the water table to wet their gills.
Crabs can be divided into three broad categories: aquatic (mostly marine), intertidal, and terrestrial. Each type is able to live only in its own environment.
The Gecarcinidae, the land crabs, are a family of true crabs that are adapted for terrestrial existence. Similar to all other crabs, land crabs possess a series of gills. In addition, the part of the carapace covering the gills is inflated and equipped with blood vessels. These organs extract oxygen from the air, analogous to the vertebrate lungs. Adult land crabs are terrestrial, but visit the sea periodically, where they breed and their larvaedevelop. Land crabs are tropical omnivores which sometimes cause considerable damage to crops. Most land crabs have one of their claws larger than the other.
More at Wikipedia
This is the first time I’ve seen or even have heard of a land crab invasion, but it’s real. True strange stuff.