Head to head
Rosy Boa vs Rubber Boa
The boa family is overwhelmingly tropical, but two small, secretive species reach well into the United States: the rosy boa and the rubber boa. Both are docile, long-lived, and kept as pets, and they divide the country between the hot Southwest and the cool North and West.
| Rosy Boa | Rubber Boa | |
|---|---|---|
| Range | Deserts of the US Southwest and NW Mexico | Cool forests of the far West, north into Canada |
| Pattern | Three lengthwise stripes (varies by locality) | Plain brown or olive, no pattern |
| Skin | Smooth and shiny | Loose, wrinkled, rubbery-looking |
| Size | ~60 to 90 cm | ~40 to 80 cm |
| Tail | Tapered, ordinary | Blunt and head-like; used as a decoy |
| Cold tolerance | Warm-adapted; underground in cold spells | Exceptional; active almost to freezing |
| Defence | Balls up around its head, releases musk | Balls up, shields head, jabs with the tail |
| In the hobby | Popular; prized for locality colour forms | Kept less often; extremely docile |
Rosy Boa vs Rubber Boa: common questions
Are the rosy boa and rubber boa really the only boas in the US?
Yes, among the true boas. The rosy boa and the rubber boa are the only members of the family Boidae native to the United States, both belonging to the small, cool-climate subfamily Erycinae along with the sand boas of Africa and Asia. Everything else that lives in or has invaded the US and gets loosely called a boa is something else: the Burmese pythons of the Everglades are pythons, and the boa constrictor is a tropical species not native north of Mexico, though escaped or released ones turn up. The two native boas are both small burrowers, nothing like the large-bodied boa constrictor most people picture.
Which makes the better pet?
Both are excellent, gentle, hardy, long-lived snakes, and the choice mostly comes down to appearance and availability. The rosy boa is kept far more widely: it is a little larger, it comes in a range of attractive striped colour forms tied to where the population lives, and captive breeding is well established. The rubber boa is arguably even more docile, almost never bites, and is fascinating for its rubbery skin and decoy tail, but it is cold-adapted, needs cooler keeping than most snakes, is a slower feeder, and is not as often bred, so it is less common in the trade. For a first snake, the rosy boa is the usual recommendation.
Why does the rubber boa have a tail that looks like its head?
It is a defence that lets the snake raid rodent nests without getting bitten on the head. When a rubber boa enters a burrow to eat baby mice or voles, the mother often attacks. The boa tucks its real head safely into its coils, raises and waves its blunt tail as if it were the head, and absorbs the mother rodent bites on the tail, which is heavily scaled and expendable. Adult rubber boas in the wild are frequently found with scarred, scabbed, or blunted tails from exactly this. The rosy boa does not do this; it relies on balling up and on simply not being found, since it hunts more by ambush near burrow entrances.