In this study, researchers observed 2,687 juvenile crabs between 1989 and 2025. The team tethered the crustaceans to posts at varying times of the year and at varying depths of Maryland’s Rhode River, a tidal estuary in Chesapeake Bay. After about 24 hours, the researchers would look for signs of predation—basically, if the crabs were dead or injured. Incredibly, they found that a whopping 97 percent of crab killings or injuries could be attributed to cannibalism—fish, meanwhile, were nowhere to be found.