Crocodiles make several sounds. Baby crocs yelp and chirp. Adult crocodiles hiss and bellow. These sounds mean something, too.
A hiss is a warning—similar to what snakes do. A yelp is a cry for the mother, and a bellow is a mating call. Bellowing is also a signal of claiming territory.

Why do baby crocodiles chirp or yelp?
Baby crocodiles make this sound to call for their mother or communicate with their siblings in a pond. Their chirp sounds like a laser shot from a science-fiction movie. The best time to hear them do this is right after they hatch.
Baby crocodiles do not just make sounds after they hatch from the egg. They also make sounds when inside the egg.The sound does not come from their movement in the eggs butfrom themselves. The sound seems to say that they want to get out.
Biologists found out that the baby crocodiles made noises while in the eggs a few minutes before hatching. The study concluded that when crocodiles make these sounds, they are signalling the siblings that it is time to hatch.
It is also a signal to the mother to remove the pile of vegetation from the nest. The researchers did this to Nile crocodiles. They started the study 10 days before the eggs were supposed to hatch.
They divided the eggs into three groups. In one group, they played the recording of the pre-hatching calls. They played recordings of other noises for another group, and then the last group had no soundplayed.
Astonishingly, the eggs in the group that heard the pre-hatching calls responded and moved. Then, the baby crocs emerged. The eggs that heard other noises moved a little, while the eggs that heard no sounds did not show any kind of movement.
From this result, the biologists confirmed that the sound from the egg is a call to their rothers and sisters—that it is time to greet the world and begin a new chapter in their lives.
Related Article: What Sounds Do Crocodiles Make?
Why do crocodiles hiss?
A hiss is a threat call, and different levels of hiss sounds represent the severity of what a crocodile feels. Crocodiles hiss to warn an enemy, telling the threat to go away.
When crocodiles hiss, they are expressing a threat. Low-level hissing can eventually escalate into an attack or a bite.
Not all crocodile hisses, however, are the same. There are two main divisions of the hiss. The first hiss comes when the animal is inhaling air, which is called “inspiration.”
The second hiss comes when the animal is breathing out or during “expiration.” The most intense hissing happens when the crocodile is breathing out, and an attack often follows it.
Some crocodiles will continue to hiss in and out before they attack. If the hiss successfully deters a threat, the croc will go back to low-level hissing and will not attack.
Crocodiles hiss to deter potential aggressors. In addition to this, they also show visual signals. For example, they open their mouths. The crocodiles also inflate their bodies. Some stand up on four legs and lunge.
Truth be told, little to no study is made about crocodiles as far as hissing and bellowing are concerned. Most of the data about crocodilians come from studies of alligators. It is merely widely presumed that these two crocodiliansbehave similarly.
Related Article: Can Crocodiles and Alligators Walk Backwards?
Why do crocodiles bellow?
Crocodiles bellow to find a mate, but they also bellow for other reasons. Some crocs bellow in such a way that it sounds like a growl.
Here are the possible reasons why a crocodile bellows:
- To deter a threat or scare off rivals
- To claim a territory
- To find a partner during the mating season
There are many crocodile species, but the mating season usually happens from October to the end of April the following year. The courtship can happen anytime between October and November. After this, the nesting period takes place for several months. The incubation period of crocodile eggs is between 80 and 90 days.
It is during this period that one could hear many crocodiles bellowing. This sound comes from the vibration when they inhale and exhale air.
Bellowing also signals to other crocs how big the bellowing croc is. The bigger the size, the more suitable it is to become a mate. As such, most crocodiles that bellow are males.
The sound of the bellow can scare off other male crocs that want the same lady. If one crocodile decides that it does not want to battle the bigger croc, no bloodshed happens.
Related Article: Do Crocodiles Mate for Life?
What is the sound of a bellow for mating?
The sound of a bellow for mating is in low frequency. As such, it is not something that humans can hear. To start the mating call, a crocodile will make vibrations in the water. This bellow causes the vibration, and it can be “seen” in the water.
The bellow has such power that it causes waves or ripples in the water. Some male crocodiles may also snap their jaws in the water. Some will bellow water from their noses.
If the crocodile’s bellow is audible, it is not a mating call. Rather, it is aggression. The crocodile is saying that the territory is his, and that the human should go away.
Now, if one sees water rippling on a crocodile’s back, it is bellowing for a mating call. It is a sight to behold, only proving that although these animals have brains the size of a peanut, they do know how to communicate.
Summary
Crocodiles make several sounds. These are the hiss, the chirp, and the bellow. Only baby crocodiles chirp and they do this to call their mother to communicate with their siblings.
A hiss from an adult crocodile is a warning. It tells an intruder to go away. The hiss is the crocodile’s way of saying that “I will attack.” Finally, the bellow is a sound to mark territory, scare off an enemy, or display a crocodile’s size to attract a mate.

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