Anegada Iguana (Cyclura pinguis) Fact Sheet: Diet & Feeding

• Iguanas are primarily or exclusively herbivorous; few other lizards eat plants. (Auffenberg 1982)
  herbivorous.
• Diet mainly leaves and fruits. (Mitchell 2000b)
  • Attracted by bright colors (Auffenberg 1982)
• Iguanas are herbivorous from hatching to adulthood; Iverson (1982) observes the young do not begin as carnivores
  • Juveniles and adults eat same proportion of plants and animals (Auffenberg 1982)
• In a population in the wild of Caicos ground iguanas (C. carinata) (Auffenberg 1982)
  • Plants comprise 96% of diet; animal prey about 4 % (termites, slugs, beetles, other insects, bird, fish, rodents, crabs)
  • Resident adult iguanas know location of food resources within their area of activity
    
• When opportunity arises, are "opportunistic carnivores" (Auffenberg 1982)
  • Eat occasionally: scarab beetles, caterpillars, centipedes, roaches, moth larvae
  • Eat insects crabs regularly, but in small numbers. (Carey 1975)
• Juvenile iguanas consume feces, perhaps to add gut bacteria to aid in digestion (Troyer 1984)

• Foraging iguanas "constantly tilt head to peer into foliage above" (Auffenberg 1982)
• Sense of smell, taste, and hearing help locate food (Auffenberg 1982)
  • Can sense airborne odors at least 200 m (656) ft away
  • Constantly lick ground or rocks, probably seeking chemical clues
  • Turn towards sound of heavy fruits striking the ground and begin active searching
• West Indian iguanas fill vital role of seed dispersers in their habitats; ecosytems depend on them. (Alberts et al 2004)
  • All seeds pass through iguanas' guts mostly unchanged (Auffenberg 1982)
• In contrast to other lizards (that are carnivorous) and to mammalian herbivores, iguanas spend little time foraging (Iverson 1982)
  • Cyclura carinata, for example, actively forages and feeds only 18% of its time.
  • Leaves quickly fill a digestive tract to capacity.
  • Food passage time is slow - 96 + hours
• Much of iguanas' diet currently is plant species rejected by free-ranging livestock (Mitchell 2000b) (Hudson et al 1994)
  • The shrub with toxic properties, Croton discolor, now supplies 30% of iguanas' diet in wild
  • Fruits (Byrsonima, Coccoloba, Eleaodendron) not taken by livestock comprise another 55 % of diet
• Strategy for eating large, stiff leaves:
  • Leaves perforated with teeth
  • Desired piece torn off along punctures
• Strategy for eating small leaves and buds:
  • Plucking and swallowing whole

Anegada iguanas often climb trees to feed.

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

Alberts et al. (2004)
Auffenberg (1982)
Etheridge (1964)
Iverson (1982)
Mitchell (2000b)