Barred Tiger Salamander larvae

Cannibal morph Barred Tiger Salamander larvae in a bucket of typical morphs larvae, Kidder County, ND.

Cannibal morphs are typically larvae and are distinguished by their disproportionally larger heads and  pronounced vomerine teeth. They get there name from their tendency to eat other barred tiger salamander larvae. The "cannibal" morphology provides a competitive advantage by  allowing them to utilize a new prey/energy source (each other) and grow to metamorphosis. The duration and amount of water in a wetland and the availability of invertebrate prey are very important predictors of salamander morphology. Cannibal morphs are typically found in small, drying wetlands where salamanders all compete for limited prey resources. In North Dakota, cannibal morphs have also been observed to co-occur with high densities of  fathead minnows (Pimephales promelas), which might be a result of increased competition for food.