Anegada Iguana (Cyclura pinguis) Fact Sheet: Behavior & Ecology

• In a study of C. lewisi on Grand Cayman Island, active periods were spent foraging, traveling, and inspecting surfaces in the environment.
• Normally spend 90% of waking hours motionless or inactive. (Dugan & Wiewandt 1982)
• Most activities are "retreat centered" where iguanas can access: (Dugan & Wiewandt 1982)
  • Shelter from climate extremes, predators, other iguanas
  • A place for nesting
  • A place for social interactions
  • Between foraging bouts, return to retreats
  • Spend night in retreats (Goodman R, 2007)
• Spend much less time foraging than carnivorous lizards spend hunting, or herbivorous mammals spend feeding (Iverson 1982)
• Most basking happens in the morning

Home range (Mitchell 2000b)

• Conditions before the introduction of livestock in the 1960's suggested both male and females have small home range less than 1 hectare (2.5 acres)
• More recent studies, that monitored long-range movements:
  • Male home range: average 6.6 ha (16.3 acres)
  • Female home range: average 4.2 ha (10.4 acres)

Chemical Communication

• Frequent tongue-touching of surfaces in environment (Goodman 2007)
  • A male C. lewisi observed inspecting and then marking an area with feces and cloacal excretions
  • Inspecting feces of other iguanas is common

Displays

• Visual displays in iguanas: (Carpenter 1982) (Martins & Lamont 1998)
  • Serve as way for individuals to recognize other individuals, and to recognize sexual and species identity
  • Serve social functions in territoriality and dominance
  • Have evolved as "ritualized fixed action patterns"
  • Marine iguanas, land iguanas, ground iguanas exhibit head bobs with little movement
  • Banded iguanas, spiny-tailed iguanas, green iguanas exhibit exaggerated head bobs and, in some species, slight straightening of front legs
  • Desert iguanas and chuckawallas employ vigorous pushups with front leg extension
• Headbobs used both in courtship activities and territorial defense (Martins & Lamont 1998)(Bissell & Martins 2004)
  • Differ among species of Cyclura
  • Smaller species use pushups; larger species use mostly headbobs (Carpenter 1982)
• Challenge displays given by iguanids: (Dugan & Wiewandt 1982)
  • Presentation of side view
  • Side-flattening
  • Head bobs
• Some Cyclura species studied have evolved a modified form of agressive displays that appease or help reduce conflict. (Martins & Lacy 2004) (Iverson 1979)
  • Probably evolved from aggressive head bob displays
  • Differ noticeably between different island populations of Cyclura iguana.

Vocalizations

• Not a significant means of communication in most lizards.

(Carpenter 1982)

• Males and females employ head bobs to convey aggression (and in courtship)
• Fighting males lash or slap each other using their tails

• Social system of rock iguanas show strong competition among males (Alberts et al. 2002)
  • Large body size, enlarged jaw musculature, prominent glands on upper leg (femoral glands) are all male traits associated with dominance
  • Largest, most dominant males defend territories during breeding season
• Head bobs (raising and lowering head in a stereotypical movement) demonstrate territoriality. (Martins & Lamont 1998) (Carpenter 1982)
• Cyclura species exhibit diverse social behavior patterns: (Martins & Lamont 1998)
  • Both sexes defend home range against same-sex individuals (most common pattern) - Rhinoceros iguana (C. cornuta)
  • Personal space aggression (defend only space around themselves) - Northern Bahamian rock iguana (C. cychlura)
  • Group living with up to 20 individuals in a group - Cuban iguana (C. nubila nubila)

• Ground iguanas help plants disperse. (Alberts et al. 2004)
• By repetitive browsing, rock iguanas prune and promote new growth in plants (Knapp and Hudson 2004)
• Exotic predators threaten survival of this species; especially cats; introduced herbivores also devastate iguana habitat (goats, cattle, donkeys) (Hudson 2001)
  • Feral cats kill most all small juveniles; few survive to adulthood (Perry & Gerber 2006)
• Researchers worry that introduced pet trade iguanas may take over habitat needed by Anegada Island iguanas. (Perry & Gerber 2006)
• Abundant land crabs on the West Indian islands obtain significant nourishment from iguana droppings (Auffenberg 1982)

• Crawl, walk and run
• Climb trees often to feed. (Goodyear and Lazell 1994)
• Can feed bipedally when plants are out of reach. (Auffenberg 1982)
• When heavy ripe fruits drop to the ground, Caicos ground iguanas (Cyclura carinata) make an "investigative charge" to find the food. (Auffenberg 1982)
• In a study of C. lewisi, none were seen swimming (Goodman 2007)

Long periods of inactivity helps an iguana conserve energy and water.

Morning hours are spent basking in the sun.

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

Alberts et al. (2002)
Auffenberg (1982)
Carpenter (1982)
Dugan & Wiewandt (1982)
Goodman (2007)
Iverson (1979, 1982)
Martins & Lamont (1998)
Mitchell (1999, 2000a,b)
Perry & Gerber (2006)