A fundamental property of an organism is its size. Ecologists like to measure trees’ diameters because they are good predictors of a tree’s biomass and thus its role in the ecosystem. Measuring tapes work well, but can become unwieldy on large trees. The hug then becomes the unit of choice. Here is a large Jacaranda…

Only a small part of Barro Colorado Island has been cleared for laboratory and dormitory facilities. Here’s a short tour of the places we stay in – a small foothold against the living forest. First, the island’s docks, where ferries and supplies come and go. The forest guards (guardabosques) who protect against poaching and other…

How best for an animal to defend itself against attack? Some succeed by virtue of their large size or ability to fight (think of a bear). But others take a more subtle path through the production of painful or poisonous chemicals. Predators prefer to avoid these animals, because consuming them is worse than consuming nothing.…

Many plants have elaborate mechanical defenses that deter herbivory. Bactris palms, for example, have a formidable spines covering the stems and leaves. For a large mammal, no part of the plant is safe to touch, but for small insects, defenses may be evaded. Evidently the cost of building spines is outweighed by the deterrent benefit.…