Bats can see.
for grown-ups
What we actually know
Yes. Bats have working eyes, and they use them. Many bats also find their way by echoes: they call out, too high for us to hear, and listen for the sound bouncing back. Echoes add to sight; they don't replace it. Many bats leave their roosts at dusk, while there is still some light. In a 2013 study, scientists estimated how far two kinds of bat could spot things by eye and by echo. Eyes were better for big things far away, like trees and the shape of the land. Echoes were better for small insects close by. So bats use both.
"Blind as a bat" may come from bats flying at night and from nobody being able to hear the calls. Bats vary a lot (there are well over a thousand kinds), and a few that live in caves see poorly, so the round says bats can see, not that every bat sees well.
New Zealand has its own bats, pekapeka: the long-tailed bat and the lesser short-tailed bat. They are our only native land mammals.
This is one of the rounds where the evidence points toward agree. The round's real subject is the saying. A child who disagrees has a real where-from (everyone says it), and the round shows that a saying can sound sure and still be wrong.
Sources: Boonman, Bar-On, Cvikel and Yovel, "It's not black or white: on the range of vision and echolocation in echolocating bats", Frontiers in Physiology, 2013 (frontiersin.org/articles/10.3389/fphys.2013.00248). The dusk point is from its abstract; the ranges were estimated from measurements, not tested in flight. Department of Conservation, "Bats/pekapeka" (doc.govt.nz/nature/native-animals/bats-pekapeka). You may read that some bats see three times better than people. We couldn't trace that to a study, so the round leaves it out.
What kids usually bring
- "Everyone says 'blind as a bat'." A saying, and Kea's reason too. Kea admits not knowing who said it first.
- "Bats find their way with sound." True, and a great thing to know. The round adds: with their eyes as well.
- "Bats fly in the dark. Nobody can see in the dark." Sensible, but many bats fly out at dusk, while there's still some light. The round asks whether dark for us is dark for a bat.
- "Bats have eyes." A good start. The record says they use them, for big things far away.
- "Bats come out when it's still a bit light." A sharp observation. The round turns it into a question: could they use their eyes then?
- "Bats don't crash into things." A clue. The record says echoes work best close by, and eyes work best far away.
At dinner
Ask: "How could you tell if an animal can see?" Then find out about pekapeka together, and whether they live near you.
Then the one rule: say their reason back before you give yours.
The round never tells your child what to think. This card tells you what we know, so you're never caught out. If your child wants to argue with it, that is the point.
