A coydog is the hybrid offspring of a male coyote

Coyote

The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...

 (Canis latrans) and a female dog

Dog

The domestic dog is a domesticated form of the gray wolf, a member of the Canidae family of the order Carnivora. The term is used for both feral and pet varieties. The dog may have been the first animal to be domesticated, and has been the most widely kept working, hunting, and companion animal in...

 (Canis lupus familiaris). Together they are genetically capable of producing fertile

Fertile

The term fertile describes a condition whereby organisms are able to produce physically healthy offspring.Fertile may also refer to:...

 young. The dogote, a similar hybrid, is the result of breeding a male domestic dog with a female coyote. Where the cross-breeding of animals is concerned, the father's species gives the first part of the offspring's name.
The prevalence of naturally occurring coydogs is problematic.