Does food taste the same to animals as it does to us?

Every day, I feed my cat small, round, hard pellets that look about as appetizing as old gravel, and she gets so excited about them. I tasted one (for you, dear readers!) and I would describe the taste as falling somewhere between the meh of cardboard and the bleh of rancid fish. Not recommended. For her part, the cat flinches if I consume an orange anywhere near her; you can tell she thinks I am disgusting for eating them. It seems pretty clear that she and I have different tastes in food. Are such differences simply matters of individual preference, or is there a biological basis for them?

As in all things, I am right and you are wrong about this.

As in all things, I am right and you are wrong about this.

It’s hard to know what something tastes like to someone else. My personal experience of peanut butter (disgusting) is likely to differ from yours (mmm, yum), despite our belonging to the same species. However, we can say with some certainty that both of us can taste peanut butter, and that it will not taste like lemons to either of us. Humans have five major types of taste receptors: sweet, umami, bitter, sour, and salty. Sugar is sweet, hamburgers and mushrooms are umami, coffee and India pale ales are bitter, lemons are sour, and salt is salty.

And mice are micey.

And mice are micey.

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Let’s talk about bird tongues

Ferruginous Hawk. Photo by Nathan Rupert*

Ferruginous Hawk. Photo by Nathan Rupert*

You don’t have to look at many birds to realize that they are very variable in appearance: hawks look different from hummingbirds, and both look different from peacocks. You can spend a lot of time looking at birds, though, before you realize that they are hiding a lot of variation inside their mouths: long tongues, short tongues, spiky tongues, curly tongues, forked tongues, frayed tongues, brush-like tongues.

Like bird bills, bird tongues are specialized to each particular bird’s way of feeding. Birds that feed on nectar have tongues specifically adapted to nectarivory, often with many little protrusions at the tip of the tongue, giving it a frayed or brush-like appearance. This brushiness increases the surface area of the tongue, making it better at picking up nectar.

Rainbow Lorikeet. Photo by Alan (Kaptain Kobold)*

Rainbow Lorikeet using its brush-like tongue to feed on flowers. Photo by Alan (Kaptain Kobold)*

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Vampire birds

The vampire strikes again! Photo by Ian White*

The vampire strikes again!
Photo by Ian White*

In honor of Halloween, let’s talk about vampire birds.

I am using “vampire” loosely here, the same way people do when they talk about “vampire” bats. These vampire birds are hematophagic (blood-eating!), but do not follow other items of vampire lore: they have reflections in mirrors, can enter your house without an invitation, do not shape-shift, are mortal, and do not sparkle in the sunlight.

Sharp-beaked Ground Finch, Geospiza difficilus

This is one of the famous Darwin’s Finches of the Galápagos Islands. This species is a vampire only on two of the islands, Wolf and Darwin; everywhere else it eats bugs and seeds like a regular finch. Even on Wolf and Darwin, it mostly eats bugs and seeds, but sometimes it craves something a little… richer…

Dum-dum-DUMMMM. (Sharp-beaked Ground Finch. Photo by budgora*)

Dum-dum-DUMMMM.
(Sharp-beaked Ground Finch. Photo by budgora*)

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What do birds do when it rains?

I’ve been meaning to write about this topic for a while—now xkcd has beaten me to it:

Oh, well. Since the comic doesn’t actually answer the question, I’m hoping you’re all still interested! (Also, at the end there will be a bonus discussion of ant rain. Yes, ant rain. You won’t find that on xkcd!)

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Featured paper: cheating Common Yellowthroats, or, the world is more complex than you think

There is a thing that happens a lot in biology, especially in animal behavior: one set of researchers finds an interesting relationship, like, say, “Birds prefer to eat bugs off of cows with lots of spots, and don’t like to eat bugs off of cows with no spots.” (This is a made-up example.)

Starlings flying near a cow; Pt Reyes, CA.

Blackbirds flying near a cow, Pt Reyes, CA.

Then, some other researchers do a study and say, “Hey, our birds prefer to eat bugs off of cows with no spots! That’s the opposite!”

Then still different researchers do another study and say, “Our birds don’t care at all about the number of spots, they just care whether the spots make a shape like a smiley face. You guys must all have made a mistake. The Smiley Face Rule is the new Lek Paradox! #nobelplease”

To put it less ridiculously: scientists get different results sometimes, and it can be hard to figure out why. Did someone make a mistake? Who is right? Today’s featured paper takes an example of this confusing scientific disagreement and elegantly makes sense of everything, with the help of this handsome little bird:

Common Yellowthroat (male). Photo by Dan Pancamo*

Common Yellowthroat (male).
Photo by Dan Pancamo*

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