Researchers identified four different camouflage hunting displays in wild broadclub cuttlefish.
Introduction
Have you ever played tag before? If you are really fast, you might be able to catch your friends. But what if you could use camouflage and sneak up on them? Then you would always be the winner, no matter how fast you were! Many predators use a similar strategy to hunt their prey.
There are two main types of predators. Camouflage can help them be more successful. Ambush predators camouflage themselves and wait until prey come close enough to attack. In contrast, pursuit predators seek out their prey like in a game of tag. Pursuit predators can be faster than their prey, like sharks and cheetahs. Pursuit predators could also have more endurance than their prey. Some pursuit predators, like wolves, even use teamwork to hunt. Many pursuit predators try to sneak up on their prey undetected before attacking.
One predator that does this is the cuttlefish. Cuttlefish are cephalopods. They are related to octopuses and squids. They have chromatophores. These are special cells that change color. All the cuttlefish has to do is flex muscles in their skin. They also have papillae that change the texture of their skin. Cuttlefish use camouflage to get near prey on coral reefs. Once they are close enough, they attack.
We wanted to know what sorts of camouflage are used by hunting cuttlefish to get near their prey. We also wanted to see what might influence these different displays. So, we took a team to the Indo-Pacific region to observe broadclub cuttlefish (Sepia latimanus) in the wild!
Methods
We observed broadclub cuttlefish on coral reefs in eastern Indonesia. We attached live crabs to the reef for cuttlefish to hunt. We used purple mangrove crabs and mottled crabs. The purple mangrove crab has a harder shell (carapace).
We recorded 254 hunting displays by cuttlefish from May 2023 to May 2024. These displays were from 98 different individuals. We saw four different types of hunting displays. We used our data to calculate the probability that we would see each of the displays. Then we looked to see if this was different between male and female cuttlefish. We also looked to see if it was different between the two types of crabs.
We saw many of the same cuttlefish multiple times. So, we also used our data to see how many different displays individual cuttlefish used.
Results
The four different hunting displays we saw were:
Leaf: The cuttlefish often changed to an olive green color. They stretched their arms out to the sides. They then approached prey slowly.
Passing-stripe: The cuttlefish changed to a grayish-white colour with moving black stripes. They stretched their arms out to the sides. They then attacked prey from straight on.
Branching coral: The cuttlefish had a variety of camouflage colours. They stretched their arms up and out to the sides. Sometimes they stretched them downward. They either attacked fast or slow.
Pulse: The cuttlefish turned a grayish-white colour with dark moving pulses. They pointed six arms forward into a cone shape and the two middle arms upward and out to one side.
We also saw some cuttlefish switching between different hunting displays. We called these mixed displays.
The probability that cuttlefish used leaf, passing-stripe, and branching coral displays was 22–29%. For pulse and mixed displays, it was 10–13% (Fig. 1).
We saw leaf displays in female cuttlefish 13% more often than in males. We also saw cuttlefish use branching coral displays 12% more often when hunting purple mangrove crabs. These crabs have a harder carapace. We saw 62 cuttlefish more than once. Of these, 79% showed two or more of the different hunting displays.
Discussion
We observed a wide variety of hunting behaviors in wild cuttlefish. We think that the hunting displays may provide different types of camouflage. In the leaf display, cuttlefish seem to mimic a floating mangrove leaf. They adopt the same color and use the same motion as a drifting mangrove leaf. The branching coral display looks like the coral reef background. Although these incredible displays stand out vividly to us, prey animals don’t spot them! This makes it much easier for cuttlefish to sneak up on their prey. They may also help cuttlefish avoid their own predators.
We saw that individual cuttlefish used a combination of hunting displays. Individual cuttlefish don’t seem to have favorites. It also means that cuttlefish are flexible in their behaviors. Each display may allow them to sneak up on their prey in a different way. This could explain why some cuttlefish used a mixed display. They may also use different displays to keep prey from getting used to one. Or, cuttlefish might just be indecisive!
In the future, we would like to explore why cuttlefish choose each of the four displays. Is it related to cuttlefish size or prey size? Is it connected to what the habitat looks like? Or is it related to the type of prey and their behavior? This information will help us better understand how and why predators behave the way they do.
Conclusion
The predatory behavior of the cuttlefish reminds us that appearances can be deceiving. Not only in the animal world, but in our everyday lives. What seems eye-catching to us might be completely different to someone else. This depends on how they see or experience the world. Like a cuttlefish’s colorful display can fool its prey, we should remember that others might notice things we overlook. You can apply this in your own life too! Keep an open mind, ask questions, and consider other people’s perspectives before jumping to conclusions. It’s a powerful way to build empathy and fully understand the world.
