THE ANIMAL FILES

Marine iguana

Amblyrhynchus cristatus

A seaweed meal ends with time in the sun.

Marine iguanas feed on algae around Galápagos shores and warm themselves after cold-water foraging. Large males may dive offshore, while many smaller individuals use exposed intertidal algae. A shared diet therefore does not require an identical route to each meal.[1]

Follow the evidence ↓
Marine iguana
Image: Sodacan · Commons · CC BY-SA 4.0
A tide-dependent table
Many individuals feed on exposed intertidal algae.[1]
Different routes to food
Large males can forage by diving offshore.[1]
Rewarming on rock
Cold-water feeding lowers body temperature.[1]

A tide-dependent table

Red and green algae dominate feeding, with preferences varying by island and availability. Low tide exposes algae for animals that remain close to shore. Gut bacteria help digestion, linking the meal to microbial processing after it has been scraped from rock.[1]

Different routes to food

Large males may dive offshore. Most females and smaller males feed on algae exposed by low tide, retreating as waves return. Some intermediate-sized animals use both methods.[1]

Rewarming on rock

After entering cold water, an iguana basks to regain warmth. Wind shelter and sun exposure influence resting positions, and overheating can prompt a raised posture that allows airflow beneath the body. Thermal management includes gaining and losing heat at different times.[1]

A COMMON MIX-UP

Does every marine iguana make a long offshore dive?

No. Many feed on intertidal algae, with offshore diving concentrated in larger males.[1]

TRY A LITTLE REASONING

Why can a sunny rock matter immediately after a seaweed meal?

Reveal the explanation

The feeding trip cools the ectothermic animal, and basking restores warmth.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Marine iguana (cited revision)
  2. NCBI Taxonomy — Amblyrhynchus cristatus

Last fact check:

One discovery leads to another

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