Are Snakes Smart?

by | Last updated Jul 21, 2013

Do snakes posses intelligence or are they purely instinctual

There is very little known about snake intelligence. Most of the information that we do have comes from keepers whose anecdotal reports and experience are often strongly divided in opinion.

The two predominant schools of thought on whether or not snakes are smart are:

  1. Snakes generally have small brains and are purely instinctual
  2. Snakes have the ability to learn and recognise not only their owners but themselves as well

Getting to the bottom of this question is no easy task. Snakes are understudied and they rely on a very different set of sensory organs to complete their daily tasks when compared with mammals. Or do they?

In 1998 David Holtzman, of the University of Rochester, decided to devise a way to determine how the brain of a snake develops and aimed to prove that snakes could learn just as well as rodents; if they were asked the right thing.

Traditionally snakes were placed under the same study conditions as rats – a maze – and were labelled as dumb when unable to navigate their way out.

“Studies that said snakes couldn’t learn well put snakes through mazes, which they didn’t learn as well as mice or rats,” Holtzman says. “But that’s asking the [snake] to do something…not natural to do.”

Study by David Holtzman to determine if snakes are smart

Dr David Holtzman with a corn snake used in the study

Dr Holtzman evened the odds for the snakes by using a two-metre wide, one-metre high black plastic tub. In the tub he had eight holes cut out of the bottom, one of which led to shelter hidden underneath.

Tape was used then used as a tactile pointer leading towards the exit hole while brightly coloured card was fixed to the wall of the tub as a marker.

The next step was to find a way to ‘motivate’ 24 Corn snakes (Pantherophis guttatus) to find shelter. Already in a relatively large and exposed space, uncomfortable for any snake, the scientists added an extra element of bright light to encourage the nocturnal snakes to find the nearest escape.

“We used an escape motivation because if we had used food, the snakes could have detected it with their vomeronasal system,” Holtzman explains. “We designed the task to eliminate chemical cues and just test learning.”

The corn snakes were then ‘taught’ by the researchers to find the escape route by guiding them with their hands.  Results were deduced from four trials per day over a period of four days during which the snakes repeatedly increased the time it took them to directly find the correct hole.

Vemeronasal or jacobson's organ is a strong snake sense

The vomeronasal or Jacobson’s organ is a strong tool in a snake’s sensory arsenal.

Interestingly, it was the youngest snakes, under three years, which learned the quickest and were more variable in the queues they used. The older snakes were slower to learn and became disorientated when the coloured markers were tampered with indicating that they rely more on sight than expected.

According to Dr Holtzman, this ability to learn comes from the fact that snakes and other reptiles have an unrestricted ability to grow new brain cells throughout their lifetimes, whereas humans can only produce limited numbers of new brain cells in the hippocampus, which controls memory and spatial perception.

Holes in the Tub – are there  Holes in the Research?

Although Dr Holtzman doesn’t claim by any means that snakes are exceptionally smart, he does believe that the results show that snakes do not wonder around aimlessly. While this is certainly true (they’re not robots after all) there seems to be something missing in the proof that snakes learn as the study claims.

One of the theories behind why snakes may learn to recognise their owners goes back to the vemeronasal organ.  Snakes are excellent at picking up chemical signals from their surroundings which are interpreted in the brain via the olfactory system.

Is it not feasible then  that snakes use these chemical queues to remember or recognise a particular smell?

Maybe  the snakes recognised their own smell, the smell of the other snakes or even the smell of the researchers’ hands in the tub and followed these queues rather than sight. What do you think?

Of course this doesn’t fully explain why the older snakes battled when the visual queues were tampered with and the details of the study, such as whether or not the tubs were cleaned each time, are not clear.

So Are Snakes Smart?

The answer is not clear. This study seems to be the only one which has attempted to determine whether or not snakes have the ability to learn.

In my own experience I have seen how the demeanor of a snake changes from when it is young to when it is an adult. Young snakes tend to be unsure of themselves; they generally strike  more readily and appear to be more nervous when confronted whereas adults are often more composed.

There is also some evidence to show that older venomous snakes have more control over their venom-delivery system and in many cases inflict a dry-bite; one in which a decision is made by the snake not to inject any venom.

Do determine whether or not snakes are smart we would probably need to define what ‘smart’ is.

If it means the ability to think, feel emotions and problem solve then perhaps snakes are not smart.

But even if this is the case, from a biological perspective they probably wouldn’t need to be smart. Evolving around the time of the dinosaurs snakes have remained relatively unchanged and are arguably the most successful predators on the planet. Why change a winning formula?

What do you think?

Does Dr Holtzman’s study prove that snakes can learn? Have you had any experiences with snake intelligence?

 

Snake playing dead with a question mark over its head.

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