The fastest animal on Earth “The Peregrine Falcon”

Though the peregrine falcon is described as the fastest animal on Earth, it is not the fastest when in its level flight which is only in the range 40 to 55 mph but in fact, when in its hunting dive. Experiments done have demonstrated that the diving speed of the peregrine falcon exceeds 200 mph. According to an experiment done in 2005 by Ken Franklin, the speed of the falcon reaches a value of 242 mph which is the fastest speed ever observed till now.

The peregrine falcon can measures from 14 to 19 inches (36 to 49 cm) with a wingspan ranging from 3.3 to 3.6 feet (100 to 110 cm). Also, it weighs from 530 to 1600 grams.

Consequently, people might wonder how such a small animal can fly at this subsonic speed? The answer lies in its ability to morph its wing.

The peregrine falcon can fly at an altitude of over 3500 feet . Initially, before diving, the falcon brings its wings close to its body. During its descent, as its speed increases, one wing tends to be pushed forwards with its head tucked in to that side while the other wing is pulled back. As for the tail, it is folded and the feet is tucked in. Consequently, that manoeuvre streamlines the bird by decreasing its cross-section presented to the air. The body of the falcon becomes more aerodynamic and air resistance is minimized.

Peregrine falcon in a dive

Another interesting question that people might point out is how is the body of the peregrine falcon adapted to perform a stoop at this speed? The falcon has special adaptations in its nostrils which allow it to breathe at such tremendous speed. Each nostril contains a rod and two fins behind it. As air rushes past the nostrils, the flow is broken up and slowed by the rods and fins which enable the falcon to breathe normally without being overwhelmed by the force at which air enters its nostrils. Moreover, the eyes of the peregrine falcon are designed so that the falcon has a clear view of its prey throughout the dive. Each eye is equipped with an nictitating membrane which protects it from dust and other debris in the air and an additional secretory gland to prevent drying up of the cornea. The dark markings around its eyes also reduce glare, improving visual contrast.

Here is a video of a peregrine falcon attacking a red-tailed hawk which is too near to its nest. Note that the red-tailed hawk is larger that the peregrine falcon with a body length of 18 to 26 inches , wingspan of 3.2 to 3,6 feet and weighs 690 to 1460 grams but this fact does not prevent the peregrine falcon to attack.

Quite an amazing video isn’t it?

Observe the extraordinary speed at which the falcon strikes the hawk. Slow motion videos show that the falcon spreads its toes open to grab the prey at the moment of contact but because of the high speed at which this occurs, it instead rakes the prey, usually with its hind talons. Since this happen so fast,  it seems like the falcon is performing a closed-foot strike.



Ryan Erf posted on October 7, 2011 at 4:47 pm

Wow, the adaptations it has made to be able to dive at this speed are incredible. I never would have thought about the complications the speed would have on breathing and sight. It’s always interesting to look not just at how a creature flies, but how it survives those flights. Do you know how its able to pull out of such a dive? The g forces must be immense and it must have a way of reducing it so its wings dont break.

Shahil Patel posted on October 7, 2011 at 6:27 pm

That’s INTENSE! I was wondering how does the falcon adjust it’s path at such a great speed?

Jean-Marc Tsang posted on October 8, 2011 at 5:36 pm

Ryan: All the articles I read about the peregrine falcon do not accurately how they pull out of such a dive. They say that when it pulls out of the dive, it experiences a force of approximately 25G. When I look closely at the videos show the dive of a peregrine falcon, I notice that in fact it does not open its wings and tail to slow its descent but instead to adjust its body to perform a loop and then it catches its prey in mid-air. According to articles, the falcon only strikes the prey, circles back and picks out of the air with its claws.
So my guess will be that it does not pull out of its dive directly using its wings and tail but instead use its speed to go upwards again ( as such force of gravity helps it slow down) and then catch its prey. The path of its dive is more like a U shape.

Jean-Marc Tsang posted on October 8, 2011 at 5:54 pm

Shahil: Usually before the falcon engages into its dive, it locates its target precisely and its tail cocks downward to help adjust to the downward angle of flight. The falcon performs minor flicks and twists of the primary feathers of its wings and tail to provide trust and adjustments to its trajectory as it tracks its prey — link to Google book:

Lorena Barba posted on October 8, 2011 at 7:46 pm

Hi Jean-Marc,
The peregrine falcon is truly amazing, and your description of the dive is very useful to get the picture.
You may want to edit the use of “supersonic” here, though; the speed of sound is about 760 mph, so a LOT more!

Jean-Marc Tsang posted on October 8, 2011 at 9:16 pm

oups my bad i mean subsonic.

Kevin Ma posted on October 11, 2011 at 2:46 pm

That’s amazing. I never thought about how much the speed takes a toll on the falcon. Do other birds have adaptations as specialized as the falcon’s?

Jean-Marc Tsang posted on October 13, 2011 at 11:18 pm

Kevin: Actually I am not sure but I don’t think that other birds have those adaptations as it is only the peregrine falcon which can dive at this speed. But other species of birds such as owls, eagles and falcons does have other adaptations which suit their purpose.

Jean-Marc Tsang posted on October 13, 2011 at 11:21 pm

Kevin: Actually I am not sure but I don’t think other birds have those kinds of adaptations as only the peregrine falcon dive at such speed. However other species of birds such as owls and eagles have different adaptions(feet and talons,beak and wings) to suit their purpose.