The Red Wolf — Canis rufus

Red wolves are beautiful; they are smaller than the more familiar gray wolf and have a reddish coat with relatively short hair. The red wolf was declared critically endangered in the 1970s. Wildlife biologists in North Carolina began rounding up healthy individuals for a captive breeding program meant to increase their numbers, ultimately releasing captive-bred red wolves back into the wild. This program is called the Red Wolf Species Survival Plan. Unfortunately, in 1980, the red wolf was declared extinct in the wild. 

There are several red wolf captive breeding programs in Florida, primarily run through the U.S. Fish and Wildlife Service. St. Vincent National Wildlife Refuge is a crucial breeding site in a semi-wild environment with two islands and two mainland tracts comprising 12,492 acres located 9 miles southwest of Apalachicola. Dozens of pups have been produced there and then transferred to a suitable habitat in North Carolina. Also participating in the program are Homosassa Springs Wildlife State Park, Tallahassee Museum, and Tampa’s Lowry Park Zoo. Jacksonville Zoo had a red wolf named Derek who participated in the breeding program until 2015.

In 2018, scientists were elated and surprised to find wild red wolves on Galveston Island, Texas. This population had hybridized with coyotes but retained important genetic markers previously thought to be lost in the wild. This was a remarkable find, considering it was the last remaining wild population of red wolves in the United States.

When I was a paleontology student in the geology department at the University of California, Santa Barbara, I was fascinated by the definition of a species, especially how it relates to the tribe of wolf-like canids, the canini. Wolves (Canis lupus) and coyotes (Canis lanterns) are considered separate species, and dogs (Canis lupus familiaris) are a subspecies. But the truth is, wolves and coyotes do not meet the scientific definition of a species, and the red wolf's (Canis rufus) species designation is especially fuzzy. 

A species is defined as “a group of organisms that can interbreed and produce fertile offspring.” Horses and donkeys are separate species because they can produce offspring (mules), but these offspring are not fertile. Mules cannot reproduce and will never be their own species.

The canid species do not play by these rules. A wolf can breed with a coyote, and a domestic dog, and their offspring will all be fertile. And this very combination of animals ultimately created the red wolf “species.”

So how were red wolves created through time? It turns out that when wolves are under stress from environmental challenges, habitat fragmentation, and human interference, wolf mates may no longer be available. Thus, wolves will look elsewhere, mating with any canid species found in their territory. Genetic testing revealed that red wolf DNA is a cross between wolves and coyotes, with the occasional domestic dog genes also present. 

Scientists theorize that red wolves were created in two distinct periods of hybridization in the ancient past, one during the ice age (~37,000 years ago) and one after the ice age (~8000 years ago), but the most recent continuing hybridization episode started approximately 200 years ago and is mainly due to the fact that in the United States the gray wolf has been largely eliminated from the lower 48 states. At the same time, coyotes have moved into the wolves' territory. As wolf numbers declined, hybridization with coyotes became more frequent and domestic dogs tended to get in the mix as well, creating the red wolf.

I find it interesting to consider how many times in the last 40,000 years wolves and coyotes have merged and then separated again, driven by intense environmental change and, most recently, the impact of humans. The hybridization that created the red wolf is a mechanism of survival, as wolves, coyotes, and dogs make their way in a changing world over geologic time.