CANIS RUFUS HAS CHANGED SIGNIFICANTLY SINCE THE IMPLEMENTATION OF THE CAPTIVE BREEDING PROGRAM, AND BOTH MORPHOTYPES ARE SIGNIFICANTLY DIFFERENT FROM CANIS LUPUS

The origin of Canis rufus (red wolves) has been hotly contested. Three main hypotheses exist: 1. It is a native North American species distinct from the grey wolves that came across the Bering Land Bridge. 2. Red wolves never were a separate species but are instead hybrids between Canis lupus (grey wolves) and Canis latrans (coyotes). 3. It is a native North American species, but not distinct from the pre-Columbian “grey wolves” that inhabited the eastern seaboard. Due to nearly complete eradication and rampant hybridization with coyotes, a captive breeding program (CBP) was created in the 1970s. In October 2021 the CBP had 266 red wolves. Whether red wolves are a separate species affects their Endangered Species List (ESL) status and therefore conservation funding, including the CBP. Without a clear definition of red wolf there cannot be a clear conservation goal. With so few individuals, it has not been clear what traits distinguish red wolves from grey wolves and coyotes. Recent years have seen the delisting and relisting of grey wolves, which heavily disrupted conservation efforts.

Cranial geometric morphometric analysis of 240 museum specimens of wild red wolves prior to the CBP, CBP individuals, and specimens of wild and captive grey wolves supports the first hypothesis. Procrustes analysis and one-way PERMANOVA (permutational multivariate analysis of variance) were completed. Red wolves from the 1970s wild populations are different from grey wolves, both wild (p=0.0001) and captive (p=0.0088). Likewise, red wolves in the CBP are different from both wild (p=0.0001) and captive (p=0.0007) grey wolves. Interestingly, red wolves produced by the CBP are significantly different (p=0.0002) from the initial wolves selected and bred. Of these four groups, the only two that are not significantly different are wild and captive grey wolves (p=0.176). This rejects the third hypothesis, as red and grey wolves are significantly different. The second hypothesis is also rejected by grey wolves being significantly different from the initial CBP red wolves. The first hypothesis is supported. This result that red wolves are a separate species from grey wolves supports their continued ESL listing. It is interesting that red wolves have changed significantly in the near 50 years of the CBP. Unique red wolf traits need to be determined.