Before the 2016 bat study, the fastest bird records came from short flight segments recorded with tracking radar and high-speed video. The bat study followed seven wild Brazilian free-tailed bats with radio transmitters from an airplane. It followed whole flights and found a median speed of 20.5 km/h, with peaks near 160 km/h.

The study took place in July 2009 near the Frio Bat Cave in Texas. It was published in Royal Society Open Science in 2016. Its peak, about 100 mph, was faster than any bat or bird measured before, as of November 2026. Wind gusts and gravity could have affected the speeds, so some scientists advise treating the data with caution.

The peregrine falcon is harder still. Stoops are hard to study because the outcome of a stoop is often difficult to observe due to its high speed. The estimate that a diving peregrine can reach about 200 mph, or 320 km/h, is credited by Live Science to a 2018 study in the Journal of Comparative Physiology A, as of November 2026.

A computer model offers a way around watching. It found that high-altitude stoops help a falcon catch erratic prey, because the extra speed gives it more force for turning, but only if its guidance is well tuned; the same study says a stooping falcon hunts at perhaps the highest speed of any animal, which puts great demands on its body, vision and control.

Tucking its wings in a stoop lets a falcon roll more quickly, because it reduces its roll inertia. In level flight a peregrine averages 25 to 34 mph when traveling, and 69 mph when pursuing prey, according to Cornell. So a falcon speeds up when it has a reason to, and pursuit is a different gear from travel.

Fish need a different kind of care. In the sailfish muscle study, the sailfish had the highest absolute speed of the four fish, but the lowest speed once body size was taken into account; the sailfish were also 50 to 80 cm longer than the other three fish, and maximum speed rises with fish length.

Using the fastest muscle twitch anywhere on the body, the study's sailfish estimate rose to 11.45 meters per second, still well below the old 35 meters per second claim. A fish would need to move forward about 3.4 body lengths per tail beat to reach 35 meters per second, but swimming fish rarely move more than about one body length per beat.

Words to know

• radar: radio tracking
• median: middle value
• erratic: unpredictable
• inertia: resistance to turning