The Proboscis bat, Rhynchonycteris naso weighs about 4 grams (80% the weight of a U.S. Nickel). This one has a baby hiding under its belly, which you can just barely see sticking out. Proboscis bats like to hang out on the trunks of trees that stick out of the water in the Neotropics. If you go for a nature boat ride in places like Costa Rica or Belize, you'll usually have these pointed out to you by your guide. They are hard to see, but they always go back to the same tree, so once your guide knows where they are, he can look like he's really good at spotting wildlife, when in reality, he just knew where the bats would be.

The Trident Leaf-nosed Bat (Asellia tridens) was my first hipposiderid, and what a beauty! I met this little guy when I was helping to teach a field course in Israel. We caught him next to a pond right by the Dead Sea. He hated being held, and he was a biter. If he couldn't get to your fingers he would just bite his own legs to show you he meant business. You've got to respect hipposiderid bats.

Ah, the famous Hipposideros commersoni. I'd always wanted to meet this bat, ever since reading about its sit-and-wait predatory hunting habits in a paper by Vaughan. We caught this beauty in Madagascar when we were looking for the sucker-footed bat. This individual was such a gorgeous orange colour, and her ears wiggled like mad when she echolocated. When we let her go, we listened on the bat detector, and after she'd flown into the darkness, the calls continued. She'd landed in a tree somewhere nearby. Maybe she was looking at us, maybe she was just cleaning herself off, or maybe she'd started hunting.

When I got started with bats, the Bent-winged bats were in the Vespertilionidae, but now they're in their own family, and I guess I'm just going to have to get used to it. I first saw Miniopterus schreibersii in Australia, but then later I saw another one in South Africa. That species is, after all, probably the most widespread bat species on the planet. I mean, some DNA study is bound to break that up into separate species, but that hasn't happened yet.

It's called the bent-winged bat because when it folds its wing, the bones look weird, like there's a big bend in one of the fingers where there shouldn't be one. Yes, different bats fold their wings up in different ways, which I think is very cool.

When I was a young undergrad, just starting to explore my fondness for bats, I dragged my friend Tobin across North America on a road trip from Edmonton to Texas, to see the famous Mexican Free-tailed Bats, Tadarida brasiliensis. They were well worth the trip, and seeing millions of bats in flight at once helped solidify my decision to become a biologist. I have been back many times since, and the bats still blow me away.

My favourite place to see Tadarida brasiliensis is the Eckert James River Bat Cave Preserve, near Mason.

Davy's Naked-backed Bat (Pteronotus davyi) does have hair on its back, but instead of the wings coming together along the sides of the body like they do in normal bats, the wings come together along the midline of the back. So the hair's hidden under the wings.

People have said that this arrangement, which has evolved independently in other kinds of bats as well, might help bats get more lift by increasing the surface area of the wings... but if that's the reason, why wouldn't all bats have naked backs? As far as I'm concerned, it's still a total mystery: Why do Naked-backed Bats have naked backs?

For millions of years, New Zealand was a paradise, free of predators. No snakes, no cats, no rats, nothing that would hurt a small animal. As a result, lots of birds started just hanging out on the ground, and many lost the ability to fly altogether. Think of kiwis, for example. Anyway, this bat, the New Zealand Short-tailed Bat (Mystacina tuberculata) started down the same road. This bat can still fly, but it spends 30% of its foraging time crawling around on the ground like a shrew. I did a good chunk of my PhD on these bats, and have coauthored three papers about them (1, 2, 3).

These bats diverged from all the other bats 45 million years ago, and they're really incredibly different from everyone else. It's sad theat they're endangered now. They're among the coolest mammals on Earth.

When I did my MSc on the New World Disc-winged Bat, I always wished that I could compare it to the elusive Sucker-footed Bat of Madagascar (Myzopoda aurita) but I was told you could go to Madagascar for a year, and maybe catch one or two. It was clearly not worth the trip.

Finally, though, in 2008, I was invited by Paul Racey to come to Madagascar to see them. His team was now working on this one hillside near the village of Kianjavato, where you could catch as many as you want. We spent a couple of weeks there, caught 31 individuals (all female) and studied the biomechanics of their sticking feet. We found out that the Sucker-footed bat does not suck. It uses wet adhesion, and it helped us understand how attachment and detachment mechanisms evolved in bats that roost on smooth surfaces.

When I was in Trinidad for my PhD, our team went to Tamana Cave to catch a bunch of different bat species for our experiments. One of those species was this little Funnel-eared Bat, Natalus tumidirostris.

We found out in our experiments that these guys absolutely will not take a single step when you put them on the ground. They always just jump into the air and start flying immediately. Most bats can at least take a few steps. So the question is: are they biomechanically unable to walk at all, or do they just really prefer to fly? We don't know.

What I do know is that these bats are so small that when they fly around you, it seems less like a small bat and more like a giant orange butterfly.

I first saw the fishing bat (Noctilio leporinus) at the Caño Palma Research Station, near Tortuguero, Costa Rica. The station manager had a bunch of bones from cooking that had filled up a freezer and one night he threw them into the river in front of the station. Suddenly the water was swarming with little fish, and then this big bat started picking them off. I had a night vision camera, and went up on top of the boat house and just watched this bat do its thing. It kept flying in circles, hitting the water with its feet where the fish were. I couldn't see how successful it was, but I watched for at least an hour, as it hit the water over and over. It was one of those magic moments of watching wildlife put on an incredible show.

When people say bats are ugly, the easiest remedy is to show them pictures of pteropodid bats, or as they're called, flying foxes. This one from Madagascar, Rousettus madagascariensis is a perfect example. Cute as a button.

Sadly, bats like these are hunted and eaten throughout most of their range. Bats make a very small contribution to human nutrition, but the bush meat trade is wiping them out. It's very, very sad. The best solution appears to be getting the people in those communities to want to save the bats, through community initiatives, but it's a serious uphill battle.

I'd read about this bat, but I didn't really understand how weird looking it was, so when I caught this individual in Fyzabad, Trinidad, I couldn't believe my eyes. The picture doesn't do it justice: his eyeballs stick way out of his head, and he just looks like a gremlin.

It's called the White-shouldered Bat (Ametrida centurio). I think he looks like Gollum from the Lord of the Rings. It's those sparse hairs on the top of the head that really do it for me. I just love this bat.

Jamaican Fruit Bats (Artibeus jamaicensis) live all over the Neotropics, and they're common pretty much throughout that range. So I've caught a lot of these guys. They're big, beautiful, fruit-eating darlings. They do well in captivity, so you can see them in a lot of zoos, and they are used in a lot of scientific experiments, too.

Common Vampire Bats (Desmodus rotundus) feed exclusively on mammalian blood, usually from cattle. That makes them parasites, which is very, very unusual for a mammal.

Most bats don't walk very much, but vampire bats often walk up to the mammals upon which they are about to feed, so vampire bats walk very very well for a bat. I did my PhD on the way bats walk, so I spent a lot of time with Vampire Bats. I published three papers on the way they move on the ground (1, 2, 3), and in the process discovered that Desmodus rotundus can run! There's a video of that here.

Any time I give a talk to school kids about bats I bust this picture out. The Honduran White Bat (Ectophylla alba) is the size of a cotton-ball, with white fur, yellow ears, nose, and fingers, and jet-black wings. Absolutely gorgeous. They roost under leaves - a male bites along the mid-vein of the leaf so it folds into a tent, and the females come live with him there.

People often ask me why these bats are white. The literature says that the light coming through the leaf from above turns them green, so they blend in, but that's not true at all. What's neat is that when I show a zoomed out version of this picture to those school kids, they don't know what they're looking at. It's not until I zoom in that they realize they're seeing bats. Maybe predators have the same issue, and maybe that's why the bats are white. I don't know.

Here's a nectar-feeding bat (Glossophaga soricina) with a baby feeding at her nipple. We caught these two together in Belize. When the pup was born, she weighed about a quarter of what her mother weighed, and by the time this photo was taken the pup was probably more than half her mother's weight. Can you imagine flying with a weight hanging from your nipple by its teeth that is more than half your mass? If that doesn't make you respect bats, nothing will.

Nectar-feeding bats can hover in front of flowers to lap up their food, and that makes them convenient for studies of animal flight. As a result, a great deal of what we know about how bats fly comes from this species.

Greater Spear-nosed Bats (Phyllostomus hastatus) eat a little fruit, but mostly large insects and small vertebrates. They live in caves, where males defend their harems of females from the approaches of other males. As a result, you have a bunch of females in a harem, who become team-mates.

If a baby falls on the floor of the cave, its mother or any other mother from the same harem will come pick it up. If a female from another harem finds the baby, she'll kill and eat it.

Do not get bitten by one of these bats. It hurts... especially if you're a baby Spear-nosed Bat.

The only time I've ever been to the Amazon was a short trip to the Tiputini Research Station in Ecudor in 2006. I was in a spot with more bat species in it than I'd ever seen in my life, and I had just a couple of nights to mist net. One of the highlights was this guy. Bats of this species, Tonatia saurophila, eat large insects and small vertebrates (saurophila means lizard lover).

Instead of letting my flash light this guy up I had a bunch of people shine headlamps on him. That really worked well. I like that he smiled for the picture. Great bat.

One day near the Caño Palma Research Station in Costa Rica, we were on a walk through the rainforest with the research station's dog. The dog suddenly dove into a hollow log, and three bats came flying out. They were pretty big, with white on the wings. We went back and set up nets that night to find out what bats were there, and found out they were Frog-eating Bats (Trachops cirrhosus).

These bats listen for the calls of male frogs that are trying to attract mates. When they hear a yummy frog, they fly in and eat it. When they hear a poisonous frog they ignore it. People say the bumps on the chin are chemosensors that they can use to kiss an unfamiliar frog to find out if it's poisonous or not. That hasn't been shown in any experiments, though. Seems like a good project for someone in the future.

Horseshoe bats are so-called because the nose leaf has a U-shaped lobe beneath the nostrils that kind of looks like a horseshoe. There are many, many species, but none of them live in the Americas, so rhinolophid bats have always seemed exotic to me.

This particular bat, Rhinolophus clivosus was hiding inside an ancient temple at Avdat, Israel. It's neat to think that throughout history, as civilizations grew and fell, the bats have been quietly living among us. I wondered whether or not that same species lived in that very temple thousands of years ago, too.

Most bats echolocate with frequency-modulated (FM) calls. That means that when they use their biosonar, they sing a song with different notes in it. Rhinolophus ferrumequinam is part of a couple of wierd bat groups that make constant frequency (CF) calls. In other words, their echolocation has just one note. Try to sing a song with one note. I guarantee it won't sound like other songs.

So when you use a bat detector to listen in to their ultrasonic echolcation calls, bats like Rhinolophus ferrumequinam sound TOTALLY different from what you're used to (assuming you're used to FM bats, I suppose).

In 2011, I went looking for bats with a crew from Daily Planet in a remote part of China, kind of close to Jinan. We searched a couple of caves but found nothing, and then finally went to this one particular show-cave as a last resort. This cave was hilarious. It had fluorescent lights everywhere, many of which flashed. It was like a weird cave-themed 80's disco from Eastern Europe or something. Very strange for me, but apparently totally fine for these cute Least Horseshoe Bats (Rhinolophus pusilus).

We did some filming in the cave, took some pictures of the bats, ate a delicious meal at the cave entrance that had been prepared by a local family, and then let the bats go and headed home. Really just a perfect day.

Rhinopomatids have those crazy long mouse tails. At the tip of the tail is a small set of hairs that are like a cat's whiskers. The bat uses the tail like a blind person uses a cane, to find its way around in the dark of the cave when crawling up rear-end-first.

I saw this bat, Rhinopoma hardwickii, in a hyrax poop-filled cave in the Negev desert of Israel.

There's a lot about these bats we don't know. One of the neatest things about them is the way they move their nostrils. The nostrils are constantly opening and closing. Are they breathing? Are they echolocating? Do they do that in flight? Great questions. Nobody knows.

I did my MSc on Spix's Disc-winged Bat (Thyroptera tricolor. This bat has little suction cups on its wrists and ankles that it uses to hold on to the smooth surfaces of leaves. My MSc project was to figure out if they actually use suction, or maybe some other mechanism like wet adhesion or Van der Waals forces to stick. Nope. They use suction. They can't stick to screen doors, but they can stick to Teflon plans. Case closed.

If you are ever in the Neotropics and you see a tube-shaped, furled leaf with its open end pointing up, look down inside. If you're lucky you might find a colony of these beauties. They're really amazing to see.

The Big Brown Bat (Eptesicus fuscus) is a very common bat in North America. I really like these guys because they have so much personality. If you look at this picture close-up, you can see that it almost looks like this one is smiling while he flies.

Big Brown Bats do well in captivity, but if you ever have to take care of a captive one, make sure you always feed it mealworms in a dish or with tweezers, not with your fingers. Otherwise, they will always bite your fingertips looking for food.

One of the first assignments I got as the co-host of Daily Planet was a trip to China. For one story, we hiked up a zillion steps to the top of this mountain, past the Buddhist temples, and into a cave that had a bunch of bats in it. At night, we set a net across the cave mouth and caught bats as they emerged. The largest of the bats we caught that night were these guys, Chinese fishing bats, Myotis ricketti. They have big feet, similar to those of Noctilio, which they use to gaffe fish.

For some reason, all the bats of this species that we caught seemed to be balding on top. I don't know whether that's just normal for this species, or if there's some kind of weird balding disease in that particular cave.

How can you not love Hemprich's Big-eared Bat, Otonycteris hemprichii? It lives in the Middle East, where it listens very carefully to the desert night with those giant ears, waiting for the sound of a beetle's feet on the sand. When it hears that, it lands on the victim, builds a little cage with its tail and wings, and then eats the insect head-first.

On my 2006 trip to Israel, I'd landed in Tel Aviv, and ridden in a taxi for several hours to Midreshet Ben-Gurion. I arrived at night and my colleagues had been catching bats right in the little area where David Ben-Gurion is buried. They had this bat waiting for me when I got there. I'd read all about Otonycteris, but those ears were way, way bigger in person than I had imagined they'd be.

It's so frstrating to know that even photos don't accurately show how incredible these animals are in person.

When I was an M.Sc. student at York University, my advisor made each of his students do a literature search on one species of bat. We had to write it in the format of the journal Mammalian Species, which is this journal in which each article is a summary of everything that is known about one kind of mammal. When we finished, we submitted our articles to the journal for publication. My article was about this bat from the Middle East that had only been described in 1960, Pipistrellus bodenhemieri. In 2001 my paper came out, but it wasn't until five years later that I finally got to go to Israel and catch the species I knew so much about. It was very exciting to know this bat so well before we'd met. He was smaller than I'd expected, and very, very gentle.

We caught this bat in Israel duing a field course I helped teach in 2006. It's a tiny little bat with a dark back and a white belly. There are so many little bats like this that are very similar in body shape, and in most places you now need DNA samples to know what species you're looking at.

I remember that when I took this picture I held the bat in a way that made her look like a hunch-back. I try not to hold bats like that for pictures now, since they don't really look like hunch-backs when you have them in your hand. It's just that they have funny flexible necks - many bats can lie with their belly against a wall and look straight out from the wall, which would be like you leaning your head back until you could see horizontally behing you.