Scientific Name:
Pituophis catenifer pumilis

Size:
    Hatch: 6.5 to 9 inches in length
    Adult: 25 to 32 inches
(possible record female of 39” still living in the Darkwoods collection)

Santa Cruz Dwarf Gophers have characteristics of their two mainland cousins, the San Diego Gophersnake (P. c. annectens) and the Pacific Gopher (P. c. catenifer). They are most similar to annectens in color and blotch count, but are nearer to catenifer in the number of ventral and subcaudal scales. Pumilus differs from those subspecies in having fewer scale rows, and most obviously in their relatively tiny adult size. This “dwarf” condition renders them unique amongst all Pituophis, for even their other island relatives (P. c. fulginatus, insulanus, and coronalis) reach adult sizes normal for the genus despite the small islands they inhabit.

I have observed pumilus to be intermediate in pattern between annectens and catenifer, and it is likely that pumilus are indeed an isolated, relict intergrade population. Hatchlings have shown the same intermediate patterns, with some having an exceedingly “busy” pattern or high blotch count similar to annectens, with others leaning toward the lesser blotch count of catenifer. The blotch count in my captive group of 6 animals ranges from 52 to 70, with the venter unmarked save for light speckling and a small triangular black mark at the outside edge of each ventral scale. Adult coloration is typically a light greenish or grayish-white background with a profuse pattern of gloss-black blotches, becoming “muddied” or less contrasting with age. Males tend to pull up some bright yellow on their anterior ventral surfaces as they grow. Hatchlings are highly contrasted, being a very light grayish-white with black patterning.

RANGE:

Limited to Santa Cruz Island, a 96 square mile land mass located 25 miles off the coast of Santa Barbara, California. Santa Cruz Island was the largest privately owned island off of the continental United States, 90% of which became the property of the Nature Conservancy in 1987. The remaining eastern 10% fell under ownership of the National Park Service in 1997.

HABITAT:

Santa Cruz Island is topographically complex. Coarse mountain ranges and deep valleys are the norm, with limited flatland. A large central valley lies between two mountain ranges for much of the island’s length. Reasonable stretches of beach are found along the island’s southern and western shores.

Due to the island’s large size and amount of geologic variation, a large variety of plant communities are supported. Coastal sage scrub, chaparral, and pine forest are all present, and are the plant associations most likely to be utilized by P. c. pumilus.

The island also supports a large population of feral pigs, which are no doubt responsible for the decline in sightings of pumilus in the wild by Nature Conservancy personnel and others.

PREY:

In the wild, pumilus most likely feed upon the two endemic species of rodent, the Santa Cruz Deer Mouse (Peromyscus maniculatus santacruzae), and the Santa Cruz Harvest Mouse (Reithrodontomys megalotis santacruzae). The introduced House Mouse (Mus musculus), is no doubt taken when found, along with occasional predation upon low-lying nests of small birds.

Wild juveniles may also feed upon the Side-Blotched Lizard (Uta stansburiana), which is also native to Santa Cruz Island.

In captivity, live, frozen-thawed, or fresh-killed lab mice are vigorously taken, as are the domesticated strains of Western Deer Mice. Live prey is quickly seized and constricted, or pressed up until the walls of the enclosure until subdued. This species is capable of constricting multiple prey items with ease.

CAPTIVE BEHAVIOR:

I have maintained a captive group of P. c. pumilus for over 10 years. Two of my original specimens are still thriving, and are barely 30” in length. Santa Cruz Dwarf Gophers are an active species, and require roomier accommodations than would a rat or kingsnake of similar size. One or more sturdy hiding places are recommended, as is a moderately sized water dish.

They are very reluctant to bite or hiss, and instead tend to struggle vigorously when grasped.

They are definitely among the more high-strung of the genus, some specimens jetting out of their enclosures and on to the floor the moment they get the chance, behaving much like a wild-caught specimen of Coluber or Masticophis. I do not handle my specimens regularly in an attempt to “calm them down”, but don’t doubt that they would become more easy to handle for anyone willing to work with them in that respect. Even just-hatched young are much more active than other hatchling Pituophis, and this innate tendency to “keep moving” may be an artifact of inbreeding amongst a small, insular population, or may have evolved as a beneficial behavior for feeding or predator evasion in their native habitat.

Pumilus are a fascinating, alert, and easy-to-care-for species, and are unique in being the only dwarf subspecies amongst a genus of “giants”. Their scarcity in private collections, and limited natural range mark them as one of the more important subspecies of Pituophis to be preserved through herpetocultural effort.

 CAPTIVE BREEDING:

Cool, rainy Winters and warm, dry Summers are the prevailing climate on Santa Cruz Island, with temperatures rarely rising above 85 degrees or dropping into the mid-30’s. This makes them perfect candidates for the “textbook” breeding system used for most North American colubrids.

Adult pumilus should be cooled separately, in a dry, darkened hibernaculum at temperatures averaging in the low 50’s. A small water dish should be provided. 8 to 12 weeks of cooling should be enough to elicit fertile mating in the Spring.

Females should be introduced into the males’ enclosures once or twice weekly following the first 2 or 3 post-hibernation feedings. Waiting for the females’ first shed may not be a reliable indicator of ovulation in this subspecies.

If the female is receptive, the male will pursue her and bite her neck, eventually aligning his body with hers, and will “romance” her into lifting her tail and exposing her cloaca with slow undulations of his body and determined attempts to lift her tail with his own.

Mating can last for several hours, and the female will typically begin to reject the male after 3 or 4 successful matings.

Four to six eggs are usually laid, with some sources reporting as many as eight. Eggs hatch in 65 to 80 days at a temperature range of 75 to 85 degrees F.

Unusually, there is a high occurrence of “twinning” in this subspecies. One of my original specimens obtained in 1990 was a “twin”, and I have produced twins in my captive group 3 times over the past 8 years. Such animals are much smaller than their clutch-mates, due to crowded conditions in the egg, but all have been strong and vigorous feeders and catch up to their siblings in size in a matter of weeks.

LITERATURE CITED:

1. Handbook of Snakes of the U.S. and Canada, Wright and Wright, 1957

 2. Snakes of the American West, Shaw and Campbell, 1974

 3. Western Reptiles and Amphibians, Stebbins, 1985 (Peterson Field Guide Series)