Animal Facts Nobody Believes Until They Check
Animal trivia has a credibility problem. So much of it is exaggerated, half-remembered or lifted from a nature documentary that took liberties, that the genuinely strange facts get lumped in with the nonsense and dismissed together.
This round separates them. Every correct answer below can be traced to published work or to biology that any zoologist would confirm without hesitation, and a couple of the wrong answers are the myths that have been circulating so long they feel like common knowledge. If a statement here sounds too odd to be true, that is not a reliable guide either way.
See all the outcomes this quiz can land on, and what each one means →
The claims that survive checking
An octopus really does run three hearts: two push blood through the gills, one drives it round the rest of the body, and the systemic heart stops while the animal swims, which is part of why octopuses would rather crawl. Their blood is blue because it carries oxygen on haemocyanin, a copper-based molecule, instead of the iron-based haemoglobin in ours.
Wombat cubes were treated as a joke until they were measured. Work presented in 2018 and developed in a 2021 study found that the elasticity of the intestinal wall varies around its circumference, so the drying material is shaped into flat-sided blocks in the last stretch of gut. The finding picked up an Ig Nobel prize, an award given for research that makes people laugh and then think.
The horseshoe crab, which is not a crab, produces a clotting agent so sensitive to bacterial contamination that laboratories developed a test around it in the 1970s, and it remains in use while synthetic alternatives are phased in. Platypus bills carry thousands of electroreceptors that pick up the faint electrical activity of prey while the animal forages with its eyes shut.
The claims that fall apart
Goldfish do not have three-second memories. Trained fish learn to associate sounds and colours with feeding and retain the association for months, and school science projects have replicated the effect often enough that it is a standard classroom demonstration.
Lemmings do not hurl themselves off cliffs. The image comes from a 1958 Disney nature film in which the sequence was staged, with animals driven towards the edge for the camera. Bulls are not enraged by red, either: cattle are dichromats and cannot pick red out the way we do, and what provokes the charge is the movement of the cape. Ostriches do not bury their heads in sand; they lie flat to avoid notice and turn their eggs in ground nests, which from a distance looks close enough to have founded a phrase.
What the number at the end is worth
This is seven multiple-choice questions, written to entertain. It has no norms, no trial sample and no percentile attached, and four options apiece means a fair share of any total can come from luck. It measures nothing about your knowledge of biology.
The facts are the part that holds. Each of the correct answers above traces back to published research or to textbook anatomy, and each of the myths has been tested and found wanting, which is a better souvenir than a score.
