Secreted Chemicals Repel and Confuse Predators

a sea hare on the sea floor is brown and soft with bright blue spots, it is surrounded by a magenta colored secretion

Biological Strategy

California seahare

AskNature Team

Image: Budak / Flickr / CC BY - Creative Commons Attribution alone

Protect From Animals

Animals–organisms that range from microscopic to larger than a bus–embody a wide variety of harms to living systems, including other animals. They threaten through predation, herbivory, defense, and parasitism, and they compete for resources such as water, nutrients, and space. Any given living organism commonly faces threats from a variety of animals, requiring strategies that effectively defend from each. Trout and other bony fish, for example, escape predators by having scales made of very thin, flake-like pieces of bone covered with slippery mucus. They also have behavioral strategies such as camouflage, fast swimming, and twisting and turning to achieve release from a predator’s grip.

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Chemically Assemble on Demand

The vast majority of biochemical assembly and break down processes––even by the most complex organisms––occur within cells. In fact, cells are able to perform hundreds, even thousands, of chemical transformations at the same time under life-friendly conditions (ambient temperature and pressure in an aqueous environment). For example, venomous snakes store precursor molecules to instantly synthesize a suite of toxins via enzyme-mediated cascades.

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Gastropods

Class Gastropoda (“stomach-foot”): Snails and slugs

There are at least 40,000 known species of gastropod, with many more yet to be discovered, making it the largest class of mollusks. These animals exhibit torsion, meaning their internal organs are twisted 180° during development. The majority of gastropods have shells, and most open up on the right side. The largest gastropods are the size of a small child (3 feet, or 1 meter) while the smallest are barely visible to the naked eye.

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Glands in sea hares secrete two compounds that protect the organism from predators by reacting together to create an unpalatable mixture of hydrogen peroxide and organic chemicals.

Sea snails and their cousins, sea hares, are extremely vulnerable creatures due to their soft bodies and limited maneuverability. To compensate for their natural disadvantages, sea hares have evolved complex chemical defenses including inks like those found in squid and octopodes. The inks are complex mixtures with remarkable properties. The secretion is composed of two viscous fluids, ink and opaline, that are produced and stored in separate s. Independently, these two substances have characteristic functions; ink is an unpalatable substance that fish avoid consuming while opaline is not. However, when combined, enzymes in ink the breakdown of s in opaline to produce new organic compounds and hydrogen peroxide, both of which are unpalatable to predatory fish and are even antimicrobial.