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Marine Life Encyclopedia

Corals and Other Invertebrates

Leaf Sheep

Costasiella kuroshimae

Distribution

Tropical to warm temperate latitudes in the eastern Indian and western Pacific oceans

ECOSYSTEM/HABITAT

Tropical coral reefs

FEEDING HABITS

Foraging predator

TAXONOMY

Order: Sacoglossa Family: Costasiellidae

Nicknamed for its sheep-like appearance and grazing habits, the leaf sheep is a nudibranch found across the Indo-Pacific. They have two dark eyes and are covered in cerata, horn-like projections that actually help them breathe. Their heads are topped with two rhinophores, which act as scent and taste receptors. The leaf sheep spends its life on Avrainvillea, a type of algae that grows in fine silt or sand. They not only live on these algae but feed on it as well. The leaf sheep is one of few animals that can perform photosynthesis. They graze on the algae and suck up the chloroplasts, storing them within the tissues of their cerata in a process called kleptoplasty. The chloroplasts provide more than just nutrition, however. They also provide protection, giving the leaf sheep a green color and chemical defenses against predators.

Like many small marine invertebrates, little is known about the conservation status of C. kuroshimae. As with many ocean species, the primary threats to the leaf sheep’s future are often climate change and habitat loss. With intensified storms and warming oceans, we risk the loss of critical reefs and nearby algae that the leaf sheep relies on for survival. In fact, a study on a relative of the leaf sheep, the sea hare (Stylocheilus striatus), showed that these animals can experience lower foraging success and slower movement when exposed to increased ocean acidification and warming.

Oceana is excited to partner with The Masked Singer to raise awareness for ocean conservation and marine life. As the Leaf Sheep takes center stage on Wednesday night, September 25, we encourage viewers to join us in taking action to protect our oceans and ensure a healthy future for the creatures that call them home. Watch the Leaf Sheep episode featuring NFL legend John Elway on Hulu.

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