Alligator Gar

There has never been a verified fatal or serious unprovoked attack by an alligator gar on a person. Despite its size, mouthful of needle teeth, and fearsome appearance, it is a shy ambush predator that avoids people and does not see anything human-sized as food. The realistic risks are minor and handling-related — a large gar thrashing in a boat or on a line can injure someone with its bony snout and teeth, and its sharp scales can cut. The one genuine hazard is the eggs — alligator gar roe is toxic to humans and other mammals and birds if eaten, causing illness, so the fish should never be used for caviar.

Because it belongs to an ancient lineage that has changed very little over a vast span of time. Gars (family Lepisosteidae) are among the few survivors of a group of fishes that was widespread in the age of the dinosaurs; fossils recognisably like modern gars go back more than 100 million years, and gar-like fishes considerably further. The alligator gar retains features that most modern bony fish have lost — heavy, enamel-coated diamond-shaped (ganoid) scales, a spiral valve in the intestine like a shark's, a vertebral structure resembling that of reptiles, and the ability to breathe air. It sits on a very old branch of the fish family tree with few close living relatives.

Its swim bladder — the gas-filled organ most fish use only for buoyancy — is connected to the throat by a duct and is lined with blood vessels, so it works as a crude lung. The gar rises to the surface, gulps a mouthful of air, and absorbs oxygen from it directly into the bloodstream through the swim-bladder wall, in addition to whatever its gills extract from the water. This lets alligator gars thrive in exactly the habitats that kill other large fish — hot, still, weed-choked backwaters and swamps where dissolved oxygen drops close to zero in summer. Young gars must reach the surface to breathe within days of hatching or they die.

Rangewide the species is listed as Least Concern, but it disappeared from much of the northern half of its historical range — including states like Illinois, Ohio, and Iowa — and is now rare or gone across the Midwest. For most of the 20th century gars were officially branded "trash fish" or "nuisance fish" believed to harm game-fish populations, and agencies actively killed them with nets, poison, and electrofishing, while habitat loss (dams, levees, and the draining of the floodplain wetlands they spawn in) did the rest. Attitudes have since reversed — the alligator gar is now valued as a native apex predator and a trophy sport fish, several states have imposed strict harvest limits, and restoration stocking programmes are under way.