Leopard, Contained

Today I watched a leopard pace in its tiny cage.  Male leopards are used to 30 square miles of home range, and this one was lucky to have 30 square yards.  This subspecies of leopard, the Amur leopard, is critically endangered in the wild, and the zoo is participating in a conservation program that likely helps to maintain biodiversity so the species doesn't go extinct.  Nevertheless, this leopard was pacing.  There was a clear path worn in the grass, and he was bored.

Amur Leopard, Panthera pardus orientalis.

Leopards are often confused with jaguars and cheetahs, but once you look carefully at their spots, you won't confuse them again.  Leopards have hollow spots, called rosettes.  Jaguars' rosettes have little black spots inside each one.  Cheetahs have solid spots.  Leopards are the largest and stockiest of the three, with large males tipping the scales at 200 pounds, though most are smaller.

Notice the empty rosettes that indicate this is a leopard, not a jaguar.

Leopards' biggest difference from other big cats is a behavioral characteristic.  They are generalist carnivores.  They will eat anything from the size of a dung beetle to a 2000 pound male eland, as long as it is in the Animal Kingdom.  They prefer prey in the 44 pound - 175 pound range, which is a bit disconcerting for a species with most of its members in the preferred prey size range.  Leopards could take humans for prey easily - their range overlaps with humans, they are well camouflaged, and they can hide around human settlements.  For some reason, leopards don't choose to take humans - they hunt all other animals preferentially.  A few leopards that were injured or sick have taken humans as prey in the past, and once they started, they kept doing it until they were killed.

As explained in a previous post, generalist predators tend to have more intellectual capacity than predators that don't have to make as many decisions or learn about as many different types of prey.  Leopards hunt alone, which means they are unlikely to evolve complex social interactions, which is likely cold comfort to their prey.  Leopards are definitely stronger than other big cats of similar size, and they have been observed hauling prey up to three times their weight high up into trees to save for a later meal.  This combination of strength and intelligence makes the leopard particularly awe-inducing to me. 

The highlight of our leopard-watching for the day was a dangerous game between the leopard and a squirrel, two smart-cookie generalist consumers.  The squirrel had found a prized piece of hot dog bun near the leopard cage and was trying to decide whether to eat it in place or carry it away to another location, a vegetarian version of the leopard's prey-stashing.  The leopard heard the leaves rustling around the squirrel, crouched, sighted the squirrel and pounced.  The leopard was denied its afternoon snack by only a thin wire fence.  The squirrel continued to appear to frolic in the leaves, rustling them unnecessarily along the edge of the cage for another minute or two before it left to gorge on simple carbs.  The leopard was as agitated as a house cat being teased with crinkly paper.  It struck me that the squirrel had learned the fence would hold and ignored the deadly but contained predator.  The leopard had not completely habituated to the fence and continued to respond to temptations on the other side.  It either hadn't learned the fence was immutable or its brain was so exquisitely tuned to the rustling prey sounds that there was no other possible behavioral response the leopard could offer at the moment.  If you have ever played with  house cat, it certainly seems that they are compelled to pounce on rustling things - perhaps it is the same with big cats.

Leopard focused on a squirrel just two feet away.

Turnips

Turnips are ridiculously under-appreciated.  They are the easiest vegetable to grow.  They are marvelously delicious.  They produce anti-cancer compounds and their nutritional profile is similar to broccoli even though they look more like potatoes.  Their greens are the richest-tasting greens of all cooking greens.  To top it all off, they are in my favorite vegetable genus, Brassica.

The picture below is of an enormous purple turnip at the Chicago Botanic Garden, a fabulous botanic garden with an extensive fall vegetable section.  This turnip is pure white on the inside (I assume - I didn't cut it open), and it should also be white below the soil.  Sunlight causes the root epidermal cells to become pigmented in this variety of turnip.  The pigment seen here is an anthocyanin, but some turnips have a green suntan from chlorophyll production. 

A gigantic turnip!

The turnip in the portrait above, since it's very large and pigmented, is likely to have some zip to its flavor, much like a radish.  The greens will be piquant as well, like mustard greens.  The root would be delicious cooked in a stew with other vegetables, and the greens could be tamed by throwing out the first round of steaming or boiling water if necessary. 

My favorite turnips are Hakurei turnips, which are pure white regardless of sun exposure, smaller, and not hot.  They are sweet and fruity and even the greens can be eaten raw.  You can find them at farmers' markets in the fall and spring.  Their texture is divine when cooked - smooth and silky, and I like them sauteed or cooked into soups.  It's absurd to think of eating turnips without the greens in my book, so I always get the roots cooking while I prep the greens.  Then I cook the greens with the roots for the last few minutes for a great combination of flavors and textures.  YUM.

Turnip and greens, Brassica rapa.

 To grow turnips, just sow a thick line of seeds and cover them with a little soil.  As the turnips grow, you can thin the young plants by collecting some greens before the roots start to fill out.  In just a few weeks the turnip roots will grow and you can harvest them as you need them for several weeks.

Turnips and butterhead lettuce.

Turnips are members of the genus Brassica, which is a group of unassuming weedy-looking plants with fast growth rates and fantastic variation in growth forms.  Each brassica species modifies a different plant part to store energy, usually in response to humans breeding the plants to make agricultural varieties.  Turnips store energy in their roots (as do rutabagas), and the rest of the plant looks pretty normal.  Other brassicas put lots of energy into leaves (cabbage and kale), leaf stems (bok choi, seen below), flower buds and stems (broccoli and cauliflower), leaf buds (Brussels sprouts, seen below), stems (kohlrabi), and seeds (canola, mustard).  It's fascinating to me that these plants are so closely related with such striking similarities in leaf and flower structures but with such vast differences in other plant parts.

Brussels sprouts, Brassica oleracea var. gemmifera.

Bok choi, Brassica chinensis.

Brassicas generally are quite nutritious and low in calories.  Consuming these vegetables regularly appears to have a protective effect against many cancers, though the mechanism is not well understood.  For optimal amounts of the cancer-fighting compounds, eat these vegetables raw or lightly steamed, not cooked into oblivion.  Some brassicas contain bitter compounds detectable by a subset of the human population.  These people can't enjoy the wonderful flavors of brassicas because they find them to be too bitter.  Also, children are better at tasting bitter compounds than adults, which explains why they more commonly dislike vegetables. 

Consciousness

I just finished a completely fascinating book about what scientists think about the human brain.  It's called Incognito: The Secret Lives of the Brain, written by David Eagleman, a neuroscientist at Baylor College of Medicine.  The book summarizes the latest ways of conceiving of and explaining the functions of the human brain.  It's a completely captivating science book and manages to also be a quick, easy read - I recommend it to everyone who has a brain.

Among neuroscientists, there is considerable debate about what consciousness is and whether other animals have it.  Dr. Eagleman wrote a compelling explanation about why humans have consciousness and who else might have it.  To explain, I'll need to start with a little background.

Animals have nervous tissue, the tissue for communicating information from one area of the body to another.  For animals like this scud, the nervous system is composed of a few neurons (cells) that can sense and carry information, as best we can tell.  The information carried in these neurons appears to be simple, like "there is more salt in the water ahead".

Scud captured in pond water (40x magnification)

It's impossible for humans to know what it feels like to be a scud, but people who study scuds are almost certain they are not conscious.  Scuds show evidence of a what Eagleman describes as modules or programs for conducting specific behaviors.  In the scud, such modules would be genetically programmed behaviors such as "swim away from the light" and "chew on rotten organic matter".  The scuds don't have choices, and they can't modify their behavior - each behavior is either done or it isn't, and there is a clear way of prioritizing behaviors so the scud doesn't have to think about it (because it can't think).

Organisms with a wider variety of behaviors have many modules for solving problems.  For example, a squirrel can eat many types of foods, and they can search for foods in many ways.  Consciousness starts to become necessary as a way of deciding which program to run in which circumstance.  Squirrels may have rudimentary consciousness, since they can choose to hunt acorns or raid the bird feeder.  Nevertheless, squirrels don't seem to be able to recognize themselves in mirrors or solve math problems.

A fat squirrel peeking out from behind a tree in Lincoln Park.

The more redundancy and plasticity in behavior types a species has, the greater the need for consciousness.  Humans have enormous behavioral variety, so we need consciousness to figure out which behaviors we're going to do when (should I hunt for food at Trader Joe's or Dominicks?).

Eagleman also points out that just because we have consciousness, doesn't mean we need to use it very often.  For activities we have learned, we have committed those skills to the comparably vaster unconscious part of our brain.  Have you ever driven across town then wondered how you managed to get there since you don't remember any stop lights or roads?  That wouldn't happen if you were driving a new route.  The apparent amnesia is a sign that you have learned the route so well your unconscious brain can handle it and let your conscious brain do other things, like learn a new song on the radio or talk to your mom on the phone.  If the routine deviates from normal, for example if a car swerves in front of you or there is a blocked road, your conscious brain takes over and figures out what to do - and you don't forget to tell your friends about the road block or near accident. 

Conscious activities are usually new activities.  When you are learning something new and doing something new, you notice so much more about the world, and time seems to go more slowly, since there is a lot more 'happening' in a conscious period of time.  Unconscious activities, like being zoned out while jogging or working or chopping onions, etc., kill a lot of time quickly without you noticing it has passed.  So the trick to getting through boring activities like waiting in line is either to zone out somehow or to turn it into a new experience.  If you want to slow down time and live a longer life (at least a seemingly longer one), have a wider variety of experiences.

Eagleman claims there are degrees of consciousness, which makes me wonder what consciousness would be like if I had an even more complex brain.

Of Birds and Meat

I saw two birds yesterday.  One was standing on the pavement next to Lake Michigan, and the other was chopped into bits in a pan in my kitchen (also next to Lake Michigan).

Inland gull hanging out in my town.

Chicken hanging out in my kitchen.

The first bird is a type I see nearly every day as I'm walking around town.  I know it's a type of seagull, though I don't know which type (never was a birder).  Seagulls are found anywhere there's water, not just at the ocean.  When they are found away from the ocean, they're often called inland gulls.  Seagulls are regarded as pest birds by some, but I love them.  They are great scavengers, and this gull no doubt is helping to keep our lake shore clean of all kinds of technically edible trash.  Seagulls are incredible fliers.  I watched one fly during the giant storm last week with gusts of wind up to 60mph, and it was doing just fine.  Since gulls are strong fliers, it means their wing muscles are strong, tough and dark in color (more on this in a minute).

All we have of the second bird to compare it to the first is its wing muscles.  Chicken's wing muscles (not the actual wings, but the breast meat - the part that actually pulls on the wings) are giant by comparison to the gull's, but despite their size, they are weak, flaccid and white.  Chickens don't use their wings, really.  Commercial chickens have been bred to have giant breast muscles, since that's the most commercially profitable part to sell in the US.   Chickens don't fly a lot when they have access to the sky, but when kept in confinement as they grow in a factory, they can't fly at all.  

The white color of commercial chicken breast meat arises from a combination of factors.  First, the genetic characteristic of chickens being more walking birds than flying birds means that their wings aren't adapted to being strong.  Secondly, these birds'  enforced lifestyle is one of all standing or sitting and no flying.  Muscles adapted to working hard, and muscles that are exercised are usually darker in color, most apparent in poultry meat.  Dark meat's color comes from its large quantities of a reddish-brown-pigmented molecule called myoglobin.  Myoglobin does the same thing as hemoglobin (the dark red protein found in the blood), but it is found in the muscles.  Hemoglobin and myoglobin both hold oxygen from the air we have breathed in.  For muscles that work harder and at fast speeds, the need for oxygen is intense.  Having myoglobin present to store extra oxygen means that muscles can work harder and faster.  Muscles can genetically have more myoglobin in them, and the quantity of myoglobin increases with increased muscle usage.

Though I have never eaten or dissected an inland gull, it would probably have dark breast meat, since it uses its wing muscles so much.  If you have ever eaten duck breast, you may have noticed that it was very dark - because ducks are good fliers.  Duck leg meat is usually lighter than the breast meat.

Time for lunch?

Gorilla Feet

I promise every post in Chicago won't be about the apes at the zoo, but there will probably be a few more after this one too!

This is a gorilla foot:

Gorilla Foot

I was able to get such a great picture because the gorilla was sleeping with his foot up on the glass.  I touched the glass after I took this pictures, and it appeared to be about 1.5 inches thick.  After seeing the adult male gorilla kick the door in his enclosure a few days ago, I'm hoping that glass is thick enough!  That gorilla is massive and extremely strong. 

Gorillas are usually fairly mellow, and they seem to have less intense social interactions than chimpanzees do.  They do engage in grooming behavior, aggression and play, but their interactions are much less constant than the chimpanzees'.  They are vegetarian, mostly forest floor dwelling and less active in general than chimps.

Gorilla's forelimbs are massive and long.  Their arms are about six times stronger than ours.  Their legs are much smaller, though still strong.  Even though they spend lots of time on the forest floor, they are still very good climbers, and they use their arms to amble around the branches and vines with ease. 

Gorilla's feet have opposable thumbs.  They are good at grasping things - branches or food, but they are not good at walking upright.  Our feet have all toes pointing forward, which is great for bipedal locomotion, but have you ever tried to pick up anything with your toes?  Not easy.

Beyond shape, there are many similarities in our feet and gorillas'.  First, scroll back up to the picture and notice the prints.  I can't call them fingerprints, because they are on the sole of the foot, but we have these too.  We have prints all over the bottom sides of our fingers, palms, toes and soles, and so do gorillas.  These prints are due to ridges in the subskin (dermis) where it attaches to the upper skin (epidermis).  The ridges and valleys allow for more contact between the two layers, which reduces separation of the layers from friction.  What that means in everyday English is that it reduces the incidence of blisters.   

Next, notice the nails.  These guys have fingernails and toenails, not claws.  Nails are good for manipulation of plants and small structures, and they protect the fingers from stomping or insect bites, but they're not good for ripping flesh.  Since gorillas are herbivores and big and strong, they don't need claws for food or defense, so they have nails.  We are not entirely herbivores, but we use tools to catch our animal prey, so we don't really need claws either.  We do, however, need to manipulate small items, and nails are useful for that.

Gorilla and human feet are homologous structures, meaning they have the same evolutionary origin, and have developed from the same bone and muscle pattern.  Since gorillas and humans separated on the evolutionary tree a long time ago (well, in evolutionary time, not so long ago) and have adapted to different environments, our feet have evolved in slightly different directions too.  Scientists think the evolutionary ancestral foot to humans and gorillas was more like the gorilla one, though probably smaller and more hand-like.  Primate ancestors were even less bipedal and more tree-dwelling. 

Zoos and Conservation

The Lincoln Park Zoo is on my daily walking route now.  It's free and open to the public, and I can power walk right through or linger and marvel, depending on how I'm feeling and what the animals are up to.  It's a small zoo, but the construction of several of the animals' enclosures allow for jarringly intimate observations of the animals.

The gorillas and chimpanzees, in particular, are housed in such well-designed pens that I find myself moved and astonished by them as has not occurred in other zoo experiences.  The floors are elevated so the monkeys eyes are level with mine and the high-quality non-distorting glass allows a 1" distance between my skin and theirs.  I can see subtle changes in facial expression, lines in the soles of their feet, and individual hairs between the fingers of grooming chimps. 

A chimp comforting another after she was refused food by a male.

The resemblance in anatomy, emotion and behavior to humans makes these animals more interesting to watch than any other in the zoo.  Their enclosure is interesting enough that they seem to feel comfortable exhibiting a variety of the complex behaviors I have read about in Jane Goodall's accounts.  They groom each other, ask for food, diffuse conflicts, climb, play and interact with their surroundings.  It is difficult not to assume one understands their motivations and behaviors, since they look so much like us.

I watched this chimp make a nest of burlap sacks, try it out several times, readjust the burlap then roll over and suck her toes.

After awe and utter fascination, the strongest sentiment I have when watching these creatures is how unfair it is that they are put on display in fancy prison cells.  They clearly have lesser environments than they would in the wild.  Their behaviors and free expression are constricted.  They are aware of the constant stream of eyes looking at them.  The big silverback gorillas protest their enclosure by sitting with their backs always to the glass.  The animals are not happy about being enclosed.  I always imagine some more powerful aliens coming to earth and capturing a few of us for their zoos at home.  We would be outraged.

And yet, there is some considerable benefit to animals in zoos from a conservation perspective.  Zoos create opportunities for the development of strong affection of humans for animals, making us care about their continued presence on earth.  We are more likely to push for the conservation of chimpanzee habitat after experiencing reverence for them in a zoo.  In the worst case scenario, zoos have been the last refuge for species that are almost extinct.  The black-footed ferret once existed solely in zoos and has been reintroduced into wild land.  Zoos also provide the means for maintenance of genetic biodiversity, by shipping sperm or arranging for matings, so that a species has a wider variety of genetic combinations, reducing the likelihood of extinction.

If it were up to me to decide to free all the animals in zoos or keep them, I would be strongly conflicted.  Clearly it unethical to keep socially complex animals in tiny, uninteresting enclosures.  As zoos expand and enrich their animals' habitats, the balance shifts more toward the value of zoos, especially since humans will apparently destroy all natural habitats without education and enforcement of the alternative.  Zoos are an imperfect solution, but it seems that at least some zoos are necessary in our current world.  I know I'm going to spend a lot of time in the ape house at our zoo while I'm in Chicago, but my amazement will always be tinged with pity.

A Love Letter to A. P. Environmental Science Students

It's getting close to Halloween, and the scariest thing for most APES students is the nitrogen cycle, so why don't we tackle that today.  The dreaded nitrogen cycle strikes fear into the hearts of Environmental Science students everywhere because it's so difficult and so necessary to know.  But just like vampires, mummies and werewolves, it gets more interesting the more you understand it (though it still might scare the you-know-what out of you!).  Don't fear - you can do this!

Do you know why I put a picture of this Chicago bean tree (actually a honey locust) here?

First of all: what is nitrogen and why do we care so much about it?  Living things on earth are mostly made of the atoms carbon, hydrogen and oxygen, but proteins need a little nitrogen.  No living thing can live without proteins, therefore nitrogen is necessary for life.  Nitrogen, however, is in short supply, at least in a usable form.  If you think of atoms like Legos, each atom would be a different type of Lego.  Atoms can bond together to make larger structures like proteins, carbohydrates, DNA and oils, which then add up to whole organisms, just like Legos can be put together to make bigger things.  Nitrogen atoms are the special Lego pieces that are rare but that you can't build anything without.  Animals get all their nitrogen from eating protein in food.  When you eat food, your body takes apart the food's Legos (atoms) so that it can put them back together again into the molecules you need (or your body burns the Legos for energy, but the analogy kind of breaks down there).

Usable form?  Take a big, deep breath - it will help calm you down, plus it demonstrates the next concept.  What you just inhaled (air, hopefully) is 78% nitrogen.  OK, exhale.  You just exhaled every bit of nitrogen that you had inhaled, absorbing none of it.  Nitrogen in the air is in the form of N2 (I don't have subscript), or two nitrogen atoms double-bonded to each other.  There is actually a triple covalent bond holding two nitrogen atoms together in N2, which makes them nearly impossible to get apart.  Think of identical Lego pieces so hopelessly stuck together that you have to go get a kitchen knife to separate them.  Your lungs don't have the biological equivalent kitchen knives, so they can't break apart the nitrogen atoms to use them, and all the nitrogen you inhale is useless to you (except that it makes our atmosphere very stable).

The Kitchen Knife Monopoly:  Nature runs a tight kitchen, and it won't let you play with knives.  Only specific soil bacteria are allowed to have knives.  By which I mean only bacteria can fix nitrogen from it's stuck form to separate, useful atoms.  The separate atoms are quickly bonded to hydrogens to make ammonia (NH3).  The name of this process is nitrogen fixation.  It is thought that the ability to fix nitrogen evolved once on this planet when bacteria were pretty much the only critters here.  Everyone else after that found that it was easier to trade with bacteria than to evolve their own way of fixing nitrogen.  It is extremely difficult to fix nitrogen because a lot of energy is required to break the triple bond between two nitrogen atoms.  Bacteria expend a lot of ATP to break the nitrogen, but no one else is going to do it for them, so they just get on with it.

Wheeling and Dealing:  Anyone else who wants fixed nitrogen has to get it from bacteria.  They can wait for the bacteria's waste and absorb that straight from the soil in the form of ammonia, but bacteria aren't very wasteful, and there isn't much nitrogen available this way.  Some organisms have found a better way to get nitrogen: they can strike a deal with the soil bacteria.  Many plants, especially legume-type plants, have a mutualistic symbiosis with the soil bacteria.  Plants provide the ATP and some oxygen in exchange for lots of ammonia.  Legumes even provide specialized little lumps (nodules) on their roots to house the bacteria. 

What About Us?  As I said earlier, we get all our nitrogen from food.  We need protein in our diet because of the nitrogen in protein.  Think of foods that are high in protein.  Did you say meat and eggs?  You're right, but think of vegetarian foods that are high in protein.  Hopefully you said beans, peanut butter and tofu.  When you think about it, you realize that all these foods are legume-type plants, which makes sense because legumes are able to get more nitrogen from housing nitrogen-fixing bacteria in their roots.

Random picture of black beans!

But that's not all is it?  Sorry, no.  When we learn about Environmental Science, we always learn about the full cycle of things - externalities, life-cycle costs, recycling, etc.  We have to finish the story.

Energy From Nitrogen?  Since it takes so much energy to break N2 apart (a reduction reaction for you chemistry folks), it would follow that energy can be had from getting those two nitrogens back together.  In fact, that's just what TNT and fertilizer bombs do is allow a large quantity of nitrogens to reunite - boom!  Bacteria in the soil can take advantage of single-nitrogen molecules and get some energy from oxidizing them in two different ways.  The first way is called nitrification, in which bacteria take ammonia molecules and make nitrite, then nitrate ions for energy.  Extra nitrate ions left in the soil from this process are very easy for plants to absorb and use.  You can think of this as half-oxidizing the nitrogens (sorry, chemistry teachers), and releasing some of the available energy.  Fully oxidizing two nitrogen compounds results in the production of N2, releasing more energy and returning the nitrogen to that useless gas molecule in the atmosphere.  (We just came full circle!)

Still Not Done:  It helps to know the following trivia about the nitrogen cycle too.  (1) Animal waste and dead organisms contain a lot of nitrogen.  Soil bacteria break down that waste and release the nitrogen into the soil as ammonia (in a process called ammonification), which is available for plants to use.  You may have noticed this if you have a dog that pees in spots around the yard that result in greener grass patches.  If your dog always pees in the same spot, you no doubt notice that too much ammonia is toxic.  (2) Agriculture results in nitrogen being absorbed from the soil into plants, then plants being carted away to markets, along with the soil nitrogen (where did all the good Legos go?).  Soil nitrogen must be replenished with chemical fertilizer, manure, growth of legumes or other fertilizer.  (3) Too much nitrogen in a body of water, say from fertilizer runoff or sewage overflows, can cause the plants to overgrow, choke out the sunlight and cause lower-down organisms to die, decompose and use up all the oxygen.  Then everything else in the water suffocates and dies.  This is called eutrophication and is worth understanding very solidly.  (4) Some single-nitrogen compounds can be made from the energy of lightning separating N2 molecules.  Also, humans use the Haber Process the break the N2 bonds to make ammonia for making bombs and fertilizer.  The Haber process uses lots of energy to split the N2.  It uses N2 from the air but gets hydrogens from natural gas (CH4), so making fertilizer is a very fossil-fuel-intensive process.