Altruism challenges purely self-interested models of human nature.

Piranhas are typically timid — mass attacks on humans occur mainly during drought when they're stressed and food is scarce.

Lightning strikes the Earth about 100 times per second.

Lightning strikes Earth about 100 times per second — producing 44 billion bolts per year.

The Catatumbo lightning over a Venezuelan lake averages 28 lightning strikes per minute — nearly year-round.

Titan arum, the corpse flower, has the largest unbranched inflorescence (flower cluster) of any plant.

Cacao trees grow their pods directly from their trunk and major branches, not from small branches.

Some conifer seeds require fire to germinate — heat from wildfires melts the resin sealing their cones.

A bolt of lightning is only about as wide as a thumb — the bright flash makes it appear much wider.