Taking a Drink


Water is an amazing molecule. The oxygen atom pulls on its two hydrogens in a way that creates a slightly-negative side and a slightly-positive side. Like opposite poles of a magnet sticking together, the molecule’s charges mean it can stick to other water molecules and even other surfaces.

Water can seem to defy gravity through a property known as capillary action. You can easily experiment with capillary action with a paper towel: dip a corner of the towel in a glass of water and watch the water creep upwards on its own. The water molecules use their charge to cling to the narrow gaps in the towel and pull other water molecules up with them.

What could this water chemistry have to do with reptiles? The Thorny Devil lizard of Australia can essentially drink through its feet – a fascinating example of capillary action in use. The lizard’s rough skin has narrow passages that allow water to climb from a puddle, up the lizard’s legs, and toward its eyes and mouth. Watch this video to see the skin changing color as the water travels, just like water moving up a paper towel.

Biologists think that some snakes also use capillary action to drink. Folds of tissue inside their mouth may form tiny tubes where water moves passively into their mouth. It doesn’t happen very often, so I felt lucky this week to catch Emory the rat snake taking a drink. It was hard to tell if she was using capillary action, but it was neat to watch!


Tough Guy

Digger the Western Hognose Snake is usually pretty docile. She arrived at the Museum in 2013 as a hatchling no bigger than a pencil. Since then, she has grown to about 30 inches long is accustomed to being handled. She doesn’t move around much during programs so her calm nature makes her a wonderful ambassador to people that might be afraid of snakes. But everyone can have a bad day – even a snake.

Digger was particularly agitated this day when I reached in the terrarium to clean her water bowl. Flattening her head like a cobra, she made herself look large while hissing loudly. Then she suddenly swung her head as if to strike. Digger was acting tough, but these small snakes rarely bite, usually striking with a closed mouth.

I didn’t want to upset her any longer and left her in peace. If her scare tactics hadn’t worked on me, she would have eventually resorted to her next line of defense: playing dead.

Zero Percent

One thing I love about the animal care community – from bird trainers to zoo keepers – is the ability to find delight in small, peculiar aspects of the daily routine. I practically jump for joy when I cut a piece of rat that weighs 100 grams, the exact meal size for Carson the Red-tailed Hawk. On a really good day, I once prepared food for 10 birds using a single, perfectly portioned chunk for each one.

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I tested my precision again this week while ordering food for the birds. The website has a handy tool showing how much space is left in the shipping box. I pay close attention to this number because frozen meat is expensive to ship and I want to fill the box as efficiently as possible. I usually end up with 2% or 3% free space in the box, not enough  for another bag of mice or quail. But this time I was excited to completely fill the box with exactly 0% of free space. How exciting! (Like I said, it’s the little things that brighten an animal keeper’s day!)

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Want to support Aldo and Carson this holiday? Consider making a donation to provide their next meal!

  • $25 would cover 2 months’ worth of Quail
  • $100 would cover 100 mice
  • $250 would cover a whole box of mice, rats, quail, and chicken

Turkey Day

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Sometimes enrichment is more enriching for me than it is for the birds. I had fun last weekend designing, cutting, and painting  custom-sized cardboard turkeys for Aldo and Carson. I didn’t realize they would be my toughest critics.

Aldo was interested at first, bobbing his head at the strange shape perched next to him. His excitement faded quickly as he turned his attention to me. I peered around the corner and waited expectantly for a photogenic reaction to my craft project. Unfortunately, the turkey didn’t get much more than a glance for the rest of the day.

Drawing Snakes

I usually rely on science to learn more about an animal or plant. I instinctively scour scientific articles, my animal physiology textbook, or field guides to answer questions. But I recently discovered how much I can learn by dipping my toes into art.

I’ve always brushed off any artistic ability with a shrug and the classic “I can’t draw” excuse. Despite my doubts, I checked out a book at the library last winter and started to learn a few tricks. I was surprised to find that drawing didn’t require innate skill; there are sets of rules that apply to any subject. Soon I was whipping out paper towel tubes and cans of beans by following the rules of cylinders. I was ready to test my pencil on a more interesting tube: a snake.

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Contour lines are the magic element that can turn a flat noodle into a 3D snake. Picture the ribbing on a can of beans. At eye level, the grooves appear as straight horizontal lines. But if I tilt the can away from my eye, the lines start to curve and create the rounded shape. By following the contour lines and adding a bit of shading, the snake comes to life!

Translating an animal to paper requires paying attention and noticing how the rat snake’s pattern or head shape differs from other snakes. I may not call myself an artist yet, but I love the way drawing makes me look – really look – at how nature is put together.

Science of Behavior Change: Negative Reinforcement

Last week I wrote about positive reinforcement, giving a reward to increase a behavior, as the most important tool in training our raptors. But every good trainer will have other tools in their back pocket to try when one method doesn’t seem to be working.

You have probably heard an incessant beeping in a car if you pull out of the garage without your seat belt fastened. After a few annoying beeps, you reach over and click the seat belt into the buckle. The beeping stops. You may not have realized it, but the car just trained you to wear your seat belt by using negative reinforcement.

Aldo dislikes having his feet touched, but with training, he usually allows me to check his foot health.

Negative reinforcement removes something unwanted (the annoying beeping stops) to increase the behavior (wearing your seat belt). Next time you get in the car, you are more likely to buckle up to avoid the noise.

I occasionally use this method during health checks with our birds. We need to look at their feet to make sure no sores develop, but Aldo dislikes having his feet touched. My hand must look big and scary to a bird that weighs less than a quarter of a pound. When I move my hand close, he pulls his foot away or steps to the side. I hold my hand in place until he stands still, then I remove my hand. He learns, “if I stand still, the scary hand goes away.” Eventually, he will let me lift a foot with my finger or a pencil.

It is not the most positive way to train the behavior since my hand is still making him uncomfortable. But he learns how to make my hand go away and has control of the situation. I also use positive reinforcement during the session with tasty mouse tidbits when he does a good job.

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Science of Behavior Change: Positive Reinforcement

Stepping onto a human’s hand, coming out of a crate, perching calmly while 50 sets of human eyes stare at him. These are not behaviors that come naturally to a raptor, but we ask our birds to do them on a regular basis. They choose to participate because of their ongoing training program rooted in the science of behavior.

There are four basic ways an animal (including humans) can learn a new behavior or change an existing one. I’ll focus on one of those methods this week: positive reinforcement.

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Aldo sits comfortably on my glove after I apply leather conditioner to his equipment.

Behavior science can get bogged down with terminology, but breaking down the basic meanings are important. “Positive,” in a behavior dictionary, means that something was added after the behavior (it doesn’t necessarily mean that it’s a good thing). “Reinforcement” means that the consequence is something the learner wants, and they will be more likely to offer the behavior again.


Imagine Cota the dog sits in front of you (the behavior). You give her a treat (the consequence). If she really likes the treat, she will probably sit again to get the tasty reward. That’s positive reinforcement!

We rely on this method with the raptors. If Carson the hawk touches the target stick, she gets a mouse tidbit. If Aldo the kestrel steps on my glove, he gets to bask in the sun in the backyard. It works on humans, too. You find a $10 bill when you turn down a new street, a second-grader gets a sticker on his perfect spelling test, you compliment your friend’s outfit. The good consequences make it likely that you will walk down that street again, the second-grader will study for his next test, and your friend will keep wearing that outfit.

By it’s nature, positive reinforcement training is fun for learners. They will work harder to gain the rewards, and it creates a strong relationship between learner and trainer. It can be challenging (almost like playing a game of Hot and Cold, but you can only say “hot” to help the person find the hidden object), but it keeps everything positive.

Next week we’ll explore another way to modify behavior and fill in another quarter of our handy chart below!

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To learn more about how animals learn, I highly recommend the classic book Don’t Shoot the Dog! by Karen Pryor.