Have you ever encountered a dead frog and wondered why it was flipped over and lying upside down? This happens for a very interesting reason.
Frogs do not die on their backs. Instead, often flip onto their backs due to the relaxation of their muscles. This relaxation, in addition to their rounded body shape, makes dead frogs more likely to roll onto their backs.
Frogs that die in water end up on their backs because gases build up in their bodies, making them float. The shape of frogs’ bodies makes them more likely to float on their backs.
Frogs Do Not Actually on Their Backs
Frogs can die in several positions. A frog that was lying on its belly when it died will stay in that position until it is affected by external factors.
If a frog just recently, died, you may find it lying on its belly, with its limbs tucked against or under the body.
Most frogs will flip on their backs only after death, due to several anatomical and physiological reasons.
Why Frogs Often End up on Their Backs After Death
The reason frogs often up on their backs after death is due to several reasons, relating to their anatomy.
Frogs have a simple skeletal structure, and a lightweight body, which is highly adapted for their agile lifestyle.
However, their anatomy also makes it easy for them to flip over when they die and can no longer control their posture.
1. Muscle Relaxation
When a frog dies, its muscles relax, which causes its limbs to splay outward.
As the limbs spread, a frog can easily flip upside down, especially if the frog was already on an uneven surface.
Additionally, since frogs are so light, a dead frog with its limbs splayed out, may have a shifted center of gravity, making it more likely for the frog to end up on its back.
2. Body Shape
Frogs have a rounded back and flatter belly. This body shape makes them unstable when they are dead and they can no longer control their posture.
For this reason, any slight disturbance can make a dead frog flip onto its back.
3. Rigor Mortis
After death, the muscles stiffen in a phenomenon known as rigor mortis.
A frog that dies rolls onto its back shortly after death can be fixed in this position when rigor mortis sets in.
4. Gas Build-up
Frogs that die in water can also be observed floating upside down. The main reason for this is the gas buildup that affects their buoyancy.
When a frog dies, it loses its ability to control its buoyancy actively.
As the frog’s body decomposes, bacteria break down the frog’s tissues. This process causes gases (mainly methane and carbon dioxide) to build up inside of the frogs body cavity.
The gas buildup makes the dead frog less dense than the surrounding water, causing it to float at the surface.
The rounded shape of the frog’s body makes it more likely to float on its back.
A Frog Flipped Upside Down May Still Be Alive
Frogs are fairly small creatures and are preyed on by many animals, such as birds, snakes, certain, small mammals, fish, and even large spiders.
For this reason, frogs have developed many ways to defend themselves against predators.
Depending on the species, frogs may rely on camouflage, toxic skin secretions, mimicry, and other tactics to ward off predators.
Some frogs will also play dead to avoid being eaten by predators. This is known as apparent death or tonic immobility.
A frog that is playing dead usually has its eyes open, its limbs sprawled, and may also roll onto its back. It may also be rigid and motionless, while being unresponsive to external stimuli .
A few species also let their tongue protrude from their mouth.
Feigning death helps frogs avoid the notice of some predators that watch for movement.
Interestingly, this phenomenon is not unique to frogs. It can also be observed in other animals such as snakes, insects, ants, spiders, small mammals, and even fish.
Frogs Are Not the Only Animals That Flip Over After Death
Frogs and toads are not the only animals that are often found dead on their backs. Many animals may also be found on their backs after death due to the same anatomical and physiological reasons.
For example, spiders legs curl up when they die, which means dead spiders often up on on their back.
Other animals that often flip over after death include lizards, ants, and many insects such as beetles and cockroaches.
Conclusion
Frogs have light bodies with a rounded shape.
Due to their anatomy, dead frogs often end up flipped onto their backs. However, this does not mean frogs die on their backs.
Most will die in the posture they were in at the moment of death, but their posture may change after death.
Also, many frogs often fake death to defend themselves from predators. This means a frog that is laying upside down, and appears dead, may actually be alive.
Frogs that are faking death typically only stay in this position for a few minutes.
Frequently Asked Questions
Why do frogs die upside down? Frogs do not really die upside down. They can die in several postures, but often end up rolled on their backs because of their anatomy, and several process, such as muscle relaxation, that occur after death.
Why do dead frogs flip over? Dead frogs flip over because of their rounded shape, gas build-up, and the muscle relaxation that occurs after death. Any slight disturbance can make a dead frog flip onto its back.
Why do toads die on their backs? Like frogs toads do not actually die on their backs. Dead toads often up rolled onto their backs because of muscle relaxation that occurs after death. Their body shape, with a flat belly and rounded back also means any disturbance can make a dead toad to flip onto its back.
Sources:
Harris, D. F. (1922). Latent Life, or, Apparent Death. The Scientific Monthly, 14(5), 429–440. http://www.jstor.org/stable/6620