TORONTO -- Does cigarette smoke linger longer than you鈥檇 expect? Are there some snakes that are actually poisonous? Here are 麻豆传媒' science and technology specialist Dan Riskin's top news stories of the week.
A MYSTERIOUS POISON ORIGIN
When people say 鈥減oisonous snake鈥� you can usually correct them because serpents are generally venomous. However, there鈥檚 one exception to this rule: the keelback snakes of Southeast Asia.
By definition, a venom hurts you after it is injected, like the venom of a snake delivered through their fangs. A poison, on the other hand, has to be eaten by the victim to work, like the skin of a poisonous frog.
Keelback snakes are poisonous. They eat toads, then move poisons from the amphibians to their own skin. But some species of these snakes are poisonous even though they have shifted their diet from poisonous frogs to harmless earthworms.
It鈥檚 been a mystery as to where the worm-eating snakes get their poison from, reveals the answer: those worm-eating snakes also eat larval fireflies, which contain the same poison as the toads.
CAN YOU IDENTIFY YOUR BABY'S CRY?
There are a whole bunch of physiological changes in a woman鈥檚 brain that happen around childbirth to make her especially good at looking after her new baby.
Collectively, this phenomenon is known as the 鈥渕aternal brain.鈥� However, it鈥檚 not always clear which of these superpowers are the result of these changes, and which are just the result of people being good at things in general. For example, a mother can recognize the cry of her own baby from a bunch of recordings of different children crying.
In the past, this was thought to be part of the maternal-brain suite of changes, that any person 鈥� regardless of gender or being the biological parent 鈥� can learn to recognize a baby from a crowd.
In other words, this ability isn鈥檛 just for birth mothers, but it鈥檚 also possible for fathers and adoptive parents. In general, the more time a person spends learning the baby鈥檚 voice, the better they perform. Also, people with more kids do better than people with fewer kids, probably also because that experience gave them more practice.
A SPEEDY LANDING FOR BEES
Speeding up to stop seems like a bad strategy, especially at the end of a flight.
on stingless bees shows that instead of slowing down when they get back to the hive, they accelerate from their steady flight speed just as they approach the entrance. Why? It鈥檚 because these particular stingless bees have a tube for a hive entrance, with a very small opening.
Computer modelling shows that slowing down would create a bottleneck. So despite the higher risk of collision injury, they land and get out of the way as fast as they can.
'THIRD-HAND SMOKE'
that even when smoking is banned in a venue, the chemicals that follow smokers in the door can have a significant impact on air quality.
Using a machine called a mass-spectrometer, which smells the chemicals in the air, researchers were able to show that in a German no-smoking movie theatre, each new audience brought with it a batch of cigarette chemicals.
The R-rated audiences (adults) brought more cigarette chemicals than the G-rated audiences (kids and parents). The effect of this 鈥渢hird-hand smoke鈥� lingered until the next day, and was as bad for audience members as second-hand smoke would be in the same theatre if someone were smoking one to 10 cigarettes while the movie was playing.
DO SICK BATS CHANGE THEIR BEHAVIOUR?
Humans are washing their hands and avoiding certain public places because of COVID-19, but what happens when bats get sick?
Vampire bats are highly social. They like to groom one another and they also sometimes share food by regurgitating meals for other bats.
decided to experimentally figure out how those social interactions changed when bats became sick, by injecting some of the animals with a harmless chemical that made them feel unwell.
These bats stopped doing less-important behaviours that might spread the disease, such as grooming, but since they still needed to eat, the food-sharing continued.
This mimics what we see with COVID-19. People are avoiding large meetings and schools are being closed in some countries, but the home is a necessary place for human interaction, and is still therefore a place where the disease is being spread.
