Anegada Iguana (Cyclura pinguis) Fact Sheet: Reproduction & Development

(Lemm et al. 2005)

• Mating May & June
• Males and females observed in managed care exhibit head bobbing and chasing behavior
• Males may bite females on the crest at the back of the neck (nuchal crest)
• Mating success among males depends on large size (Dugan & Wiewandt 1982)

Nesting

• Females dig nest late June-July (after spring rains)
• Tunnels dug by females are deep - 90 cm (3 ft.) deep; up to 320 cm (10.5 ft.) long, (Gerber & Lemm unpublished data)
  • Nests deeper than seen in other Cyclura species (Lemm 2005)
• Females lay up to 20 eggs; 13 is average (Bradley & Gerber 2005)
• Successful nesting involves: (Lemm et al 2005)
  • Female places eggs in a recently dug nest (doesn't scatter eggs)
  • Female lays eggs in only a few hours (doesn't take longer)
  • Female covers nest and defends it (for up to two weeks)
• Female egg/nest guarding important in environments where nesting sites are scarce (Shine 1985)
  • Egg guarding in lizards occurs when parents are large enough to deter a predator (de Fraipont 1996)
  • Egg guarding more common in large species; live-bearing lizards tend to be smaller (de Fraipont 1996)

Incubation

•  About 90-92 days, with nest temperatures being about 30.5-31.0°C (Perry et al. 2007; Lemm and Alberts 2012)

Eggs

•  In the wild, females lay 1 clutch of up to 20 eggs; 13 on average (Gerber 2005)
• On average, 64.8 mm long by 45.0 mm wide; weight 62.7 g on average (Lemm and Alberts 2012)

Hatchlings

• Hatchling weight: 47.0 g, on average (60 g on Guana Island) (Lemm and Alberts 2012)
• Emerge late September to October in wild
• Dominance interactions frequent among hatchlings (Alberts et al 1997)
• Disperse rapidly away from coast to higher elevations, especially on Guana where they have been introduced

Young

• By 2-3 years in age and 20 cm (8 in) length with 30 cm (12 in) tail, able to survive life with feral cats (Carmignani 2010)
• Female rock iguanas reach sexual maturity 7-9 years of age (Wiewandt 1982; Jeff Lemm, personal communication, 2017)
  • Researchers studying Turks and Caicos iguanas that have been translocated note faster growth rates (sexually mature at 2-4 yrs. rather than 6-7 yrs); less crowding and competition with other iguanas may promote faster development (Gerber & Alberts 2005)
• Average growth rate for 1st 6 mos in managed care:
  • 0.67 g/day (0.02 oz/day) (Lemm et al 2005)
  • Growth rates measured for a few wild iguanas on Anegada show faster growth. (Gerber unpublished)

Adults

•  Continue growing slowly throughout life. (Dugan & Wiewandt 1982)

• Not yet established empirically, but typical life expectancy is probably 60–80 years (Jeff Lemm, personal communication, 2023)
  • Iguanas live longer than most lizards (Dugan & Wiewandt 1982)
• Carey (1975) stated 40+ years

• C. pinguis evolved in a "predator-poor" environment (Bradley & Gerber 2005)
  • Producing just a small number of eggs, this species is especially susceptible to losses from introduced predators
  • Feral cats preying on juveniles threaten survival of these rare lizards. (Lemm et al 2005)
• Other causes of mortality: (IUCN 2010)
  • Grazing pressure from free-ranging livestock
  • Predation by feral dogs
• Native snakes (Puerto Rican racers, Alsophis portoricensis) and a kestrel observed preying on Anegada Island iguanas that were translocated to Guana Island. (Levering & Perry 2003)

Anegada iguanas take a long time to reach reproductive maturity—about 7-9 years!

This species' recovery is also hindered by small egg clutches and predation by non-native animals, such as feral cats.

Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.

This wild nest is being studied by conservation scientists with San Diego Zoo Wildlife Alliance.

In the wild, female Anegada Iguanas lay an average of 13 eggs per clutch.

Image credit: © Jeff Lemm. All rights reserved. Used with permission from the artist.

Wild Anegada Iguana hatchling.

Image credit: © Jeff Lemm. All rights reserved. Used with permission from the artist.

Alberts et al. (1997)
Bradley & Gerber (2005)
Carey (1975)
de Fraipont et al. (1996)
Dugan & Wiewandt (1982)
Gerber (unpublished)
Lemm et al. (2005)
Mitchell (2000b)
Perry et al. (2007)