Bumblebees & chimps, skin eating baby worms, & electric fish sensors | Last Week in Science (10 March 2024)

Is learning from others our super power?

One of the reasons for success of humans as a species is considered to be our ability to learn from the inventions of others and then build up on it. But it seems this is not an ability that is unique to humans. There are examples of pigeons who improve their flight by learning from each other but it is not as spectacular as what humans can achieve, like bringing a new iPhone model each year or foldable mobiles.

Researchers have now found that such learning can happen in our close relatives - chimpanzees too. When chimps were given a vending machine from which they can get peanuts after doing a task that is simple for us but a complicated maneuver for them. The chimps had to take a ball, open a drawer, put the ball in a slot and then close the drawer. For three months they tried but none of the 66 chimps they tested could figure out how to get the pack of peanuts from the machine. The researchers then trained two of the chimps as to how to use the machine. The other chimps were then made to see how the two chimps got peanuts from the machine. The researches then saw that 14 of the observer chimps learnt how to do this task. One may argue that chimps are smart and are known to make tools so it is not that big a deal.

But in another study, researchers made similar observations on bumblebee. The bumblebees had to remove a block to gain access to another block that when pushed will give them access to sugar. The researchers gave 24 days to bees to solve this puzzle on their own but they could not do so. But when they trained 9 bees and made 15 other bees see them solving and reaching the sugar reward, 5 of these 15 bees also learnt from this demonstration. It seems that learning from others may not be our super power.

Reference: Bees and chimpanzees learn from others what they cannot learn alone

Mystery of baby worms that feed only once a week

More than 20 years back scientists found a type of worm - caecilian- who would feed on the skin of their mother worm. They would do this once a week. It was astonishing because how can these baby worms survive with feeding just once in a week. To solve this mystery, scientists recorded the worm behavior for 200 hours. What they found was the young worms would make clicking sounds which would cause the mother to release a nutrient rich liquid - similar to milk, from its cloaca - opening of the body at the end of the digestive tract that is an outlet for both the digestive and reproductive system. The worms were also moving their heads inside the cloaca to feed.

Other species of this type of worm are known to release milk like liquid to the unborn worms that hatch inside their bodies. But the worms that were studied by the researchers hatch outside the body and feed on their mother's milk.

Reference: Got milk? Meet the weird amphibian that nurses its young

Story of electric fish sensors

Just like bats use sound for locating objects in their surroundings, electric fish use electrical signals to do the same. Since fish move in groups, one may wonder how the electrical signals of a fish would not interfere with that of the other fish. And scientists too have been focusing on their studies to understand the same. So, fish keep adjusting the frequency of their electrical signal pulses to ensure that they don't jam the signals of another fish in their shoal. In a recent finding, scientists have discovered that in one species of electric fish - elephantnose fish, the signal of another fish in their group is used to their advantage.

Sensing devices like sonars, radars and some CT scanners use multiple sensors to increase their field of sensing. Elephantnose fish also do the same by using other fish's signals. The information that comes back from the nearby fish helps them to sense a larger area of their surrounding environment.

Reference: Collective sensing in electric fish