I often recommend live-bearing species to folks interested in getting started on breeding reptiles and amphibians. If given the proper environment, live-bearing moms take care of the hard work of incubation, leaving us to enjoy the offspring. But livebearers are certainly not for beginners only (nor are they all “easy”…sorry!) – in North and Central America’s Swifts, also known as Spiny or Fence Lizards (Genus Sceloporus), we are presented with over 90 fascinating species ranging from the very hardy to the rarely kept or bred. A number of readily available species give birth to live young.
Swifts in Captivity
Ever since boyhood, when a female Yarrow’s Swift (Sceloporus jarrovi) arrived in the mail complete with 7 miniatures of herself born on route, I’ve been a great fan of this group.
Robust, active and attractive (males in breeding condition are among the most brightly colored of all lizards), many species make hardy captives if kept properly. Captive essentials for most include a larger than average enclosure, basking sites of 95-100 F, abundant UVA and UVB, and a diet comprised of a wide variety of invertebrates. Please write in for information on the care of individual species.
Courtship and Breeding
When in breeding condition, males are impossible to misidentify, being clad in bright colors (often a shade of blue) and ever-ready to display. At other times, their thick bases help distinguish them from the more somberly colored females.
Male Swifts are absolutely intolerant of one another – even in room-sized exhibits I’ve had difficulty in maintaining more than a single male. Intruders are met with complex displays, followed by serious fights if one does not retreat.
Courting males engage in species-specific head bobs, after which they may head-butt and lick the female. Females are usually bitten on the shoulder during copulation.
Gravid females swell noticeably, and the young can be seen moving about as their birth approaches. Depending upon the species, 4-18 perfectly-formed little lizards may be born.
Field Research on Sexual Signaling in Swifts.
Video of a Blue Spiny Lizard showing the typical alert demeanor and robust build.
Swift Ventral Side image referenced from wikipedia and originally posted by Tigerhawkvok
Swift Lizard image referenced from wikipedia and originally posted by Walter Siegmund