Trunk Protected From Predators

a tall spiky plant with flowers on top stands on the right of the photo overlooking a hilly landscape

Biological Strategy

Halfmens plant

AskNature Team

Image: Paul Godard / Flickr / CC BY NC ND - Creative Commons Attribution + Noncommercial + NoDerivatives

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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Flowering Plants

Clade Angiosperms (“receptacle seed”): Dandelions, oaks, grasses, cacti, apples

With 416 families containing some 300,000 known species, angiosperms are the most diverse group of plants, and they can be found around the globe in a wide variety of habitats. They are characterized by seeds that grow enclosed in ovaries, which are enclosed in flowers. The floral organs then develop into fruits of myriad kinds and dimensions, from simple seed casings on maples to elaborate fleshy growths like papayas. The oldest flower known from fossils, Montsechia vidalii, appeared during the Jurassic Period 130 million years ago. They are the primary food source for herbivorous animals, which in turn makes them the indirect food source for carnivores as well.

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The trunk of the half-mens plant is protected from damage by thirsty animals thanks to a covering of long spines.

Image: Martin Heigan /

Image: Er.We /

This photo shows the protective spines.

Image: Robert Jacob Gordon / Public Domain - No restrictions

Painting of Pachypodium namaquanum Welw. ("Halfmens") with spines visible.

“The half-mens [Pachypodium namaquanum], growing in the same [Namib] desert, has reduced its leaves to one small bunch sprouting from the top of a pillar-like trunk bristling all over with ranks of long spines that must deter many a thirsty animal from gnawing it in search of liquid.” (Attenborough 1995:272)