On land, snakes have extraordinarily strong senses of vision, smell, and hearing, which not only make them efficient predators, but also help them evade enemies as well.
If you’ve ever noticed, it can be really difficult to catch a snake. They’re fast, and it seems like they’re always one step ahead of you because they have such sensitive sense perception.
Of course, when it comes to sea snakes, you can expect that the senses of smell, vision, and hearing aren’t as clear. Water tends to muffle out these senses, and yet, sea snakes seem just as efficient at the things they do as land snakes. How can this be?
New research published in the Royal Society journal Open Biology suggests that sea snakes must have another sense we know little about.
Since they are still amazing hunters even under water, and the senses we know land snakes would rely on while on dry land wouldn’t be as effective under water, it only seems to make sense that there must be another source of sea snakes’ responsiveness and sensitivity.
The report details that on the heads of sea snakes are these little sensory organs known as “scale sensilla.” To you and I, they look like ordinary scales, but on either side of the snake’s head, where you would expect their ears to be, there are some special scales instead. Scale sensilla are used by land snakes to detect the sense of touch.
The study noted that sea snakes have much more dome-shaped sensilla scales than land snakes do, and this would suggest that sea snakes probably use the sense much more.
Image Credit: Jenna Crowe-Riddell
In a water environment, where water is constantly flowing across the faces of sea snakes as they swim, their scale sensilla would need to be much more sensitive to feel the smaller ripples in the water to detect movement and vibrations.
“We believe sea snakes use these organs to sense objects at a distance by ‘feeling’ movements in the water,” says lead author Jenna Crowe-Riddell, a PhD student of the University of Adelaide. “This hydrodynamic sense is not an option for land animals. In water, a new way of sensing the environment becomes possible.”
As other critters swim, their forceful propulsion through the water sense movement waves through the water, just as dropping a pebble into a body of water would send ripples through the surface.
What the researchers are suggesting is that the larger scale sensilla found on sea snakes may be much more capable of detecting these kinds of waves, and hence helping sea snakes detect movement under water.
This is a skill that land snakes do not need because they have great eyesight and hearing in addition to the sense of touch.
There is no concrete evidence just yet, but the hypothesis seems solid enough for some testing to learn more.
“What we now need to do”, says lead scientist Dr Kate Sanders, “is to investigate the physiology of these scale sensilla and demonstrate exactly what they can sense. If they are hydrodynamic tactile sense organs, as we suspect, then by comparing them to the scale sensilla of closely related land-snakes we can start to understand how evolution has changed these organs from direct-touch sensors to distance vibration-sensors that work underwater.”
Do sea snakes have another sense that land snakes don’t? Well, they probably have the same sense, just amplified 1000x.
We won’t really know until further testing is performed to see just what sea snakes can sense that regular land snakes cannot.
It is worth noting that even land snakes have the ability to swim under water, but sea snakes are specially built for water-logged environments. Their tails are vertically flattened to help them produce thrust as they push against the water to move forward. Ordinary snakes have the same skill, but without their paddle-like bodies, they move less efficiently.
What can learn from this is that sea snakes have adapted from their origins to better take on a water environment, and this is the explanation for the differences between the bodies of a land snake and a sea snake.
Source: The University of Adelaide