Wednesday, May 30, 2012

Indoor Cats: It's Only Natural

When I was growing up, I had a cat named...I'm not making this up...Kinky. This is what happens when you let children name a cat. He had kinks in his tail, hence: Kinky. I grew up a cat lover and had Kinky by my side for 14 years. 
Me and my big sister, Jenny, with Kinky in the window (before he put on a few pounds). 
What my sister was up to in this picture, I have no idea, 
but it probably involved corrupting my sweet, innocent, 2-year old mind.

On occasion, we'd let Kinky roam outside, but always accompanied. We were too worried that he'd meet his end either via vehicle or neighborhood dog. I always joked that Kinky posed no threat to wildlife as birds spent more time terrorizing him than he did them. That and the fact that my cat weighed 20 pounds would probably have made him a pretty poor hunter.  

The truth is that cats are in fact superb hunters, relying on thousands of years of instinct to catch their prey. They are some of nature's finest predators, and this includes our own pets. There are three kinds of domestic cats you will encounter outside: "outdoor cats", strays, and feral. "Outdoor cats" are those that are allowed to freely roam outside by their owners, whereas strays are ones that have either run away from their homes or have been abandoned by their owners. Feral cats are those that have never been a pet; they were born in the wild. The issue of outdoor cats is a long-contested and hot button topic. Today, I thought I'd answer what are some of the most common questions and comments that I hear about cats.

Cats are a part of nature, and they have to eat too. Why is it bad that they eat wild animals?
The answer here is that domestic cats (Felis domesticus) are not a part of nature. They have been bred for thousands of years to be a companion to man, to dwell along side of us within our households. A cat is no more a part of nature than a domestic chicken, dog, or hamster.

This is why outdoor cats are such a sensitive topic among biologists--they are not a native and wild species but are having a profound impact on true wild native species. They not only cause a decrease in bird populations (cats are the number one cause of mortality for birds), but threatened and endangered species of other animal groups as well, including sea turtle hatchlings.

I think this is the expression Kinky would have
 had if we made him wear a collar like this.
What if I put a bell on my cat's collar?
Cats are very, very, good hunters, and can learn to sneak along without causing a single bell chime. And because cats with bells on their collars learn to adapt their hunting style, it actually makes them even better and more efficient predators.

"I swear I wasn't going to put this
at the foot of your bed."

If I feed the stray/feral cats, they won't need to hunt. 
This is one of the most common misconceptions about stray and feral cats, and unfortunately it is not true. Even a well fed cat still has its predatory instincts intact and will still hunt. A great example of this is cat owners who find little "gifts" in their house such as birds and lizards. The cats are well cared for and fed, but still catch and kill wildlife.

In addition, feeding stray and feral cats only causes their populations to increase. When an animal has ample resources for survival, its body's response is to breed. By providing more than enough food that the cats need to survive, they breed frequently and populations skyrocket. A female cat can start to breed as early as five months of age, and can have two to three litters a year. I may not have my calculator handy, but I can tell you that is a lot of cats! (But if you really want to see the math, look here)

Cats only pose a risk to the animals that they hunt.
Feral cats have introduced Feline Panleucopaenia (FPL), closely related to the lethal canine parvo, into not just other domestic cats, but wild cat species as well such as bobcats and panthers. Untreated, FPL has a 90% mortality rate. In Florida, the endangered Florida panther population has contracted FPL, further contributing to their decline. 

So what can I do?
If you do see a stray or feral cat in your neighborhood, please do not feed it. Contact a local shelter or cat rescue; they may be able to help you find a home for your feline friend. If you have an outdoor cat, it is possible to convert it to be an indoor cat--be patient and stick with can do it! There are many resources online for helping your cat (and yourself) make the transition from the urban to the indoor jungle while making sure your cat is still enriched mentally. Indoor cats live longer, healthier lives and in turn your backyard wildlife will live longer and healthier lives too! 

Thursday, May 24, 2012

What's the Big Deal? The Japanese Spider Crab

It's time for some behind-the-scenes Nature Geek info. Every week when I publish a new post, I geekily sit here and watch the metrics on my blog. It's kind of like stalking...from the other side. I watch to see how long it takes for the first person to read the post, and how many people read my post within an evening (the answer: literally tens of you). I can also look at the all-time history of my blog to see which posts are the most popular. 

I moved my blog from Facebook to Blogspot in October of 2011 and since then my top posts have received about 150 to 400 views. However, even my #2 most popular post of 420 views, "Test Your Turkey Trivia!" is a drop in the bucket compared to my most popular entry, "It's Always Halloween in the Natural World." How many views has it received? 17,172! And the reason? People Googling for this picture of the Japanese spider crab.
This is one popular crab.

So just what is the fascination with Japanese spider crabs? I decided to find out.

Let's start with the obvious: its size. Japanese spider crabs are the largest and longest lived of all crabs, with a lifespan of up to 100 years and a legspan of up to 13 feet (4 m). Just imagine a crab able to straddle your bed and peer down at you with its beady eyes. 

Are you sleeeeepy?

However when you look at the body alone, it's really not that large. Sure, it can be about the size of a basketball and weigh up to 44 pounds (20 kg), but when you consider the heaviest American lobster ever recorded was of equal weight and its total body length was only around 2 feet (0.6 m), the Japanese spider crab is really a lightweight. 

Typical of crabs, the Japanese spider crab is a scavenger. They roam the ocean floor, down to a depth of up to 2500 feet (800 m), feeding on animal carcasses they come across. Stories have been told of spider crabs feeding themselves with the bodies of those who have died at sea, which in reality is quite plausible. But with their reported gentle nature and relatively small front claws, a Japanese spider crab isn't exactly going to pull you out of your boat (plus again the crab is a scavenger, not a predator). If there was a crab that I would be afraid of coming after me, it would be this guy, the coconut crab.
This man looks like he's about to get a nipplectomy from that coconut crab.

If the Japanese spider crab were to enter a Miss Benthic contest, it would surely win. I mean not only would it clearly have the best legs in the competition, but it has a pretty good platform as well. With those long legs, Japanese spider crab tendons are often used in research. There is even research being conducted right now on using the crab's tendons for nerve regeneration. That would most definitely beat out the platform of the hagfish, which is "copious slime production for all." 
The next Miss Benthic? I think not.

So there you have it, Japanese spider crab lovers, some information on your favorite crustacean. Thanks for stopping by my page and while you're here, post a comment on just what teacher out there is obsessed with research papers on spider crabs; I'd really like to thank him or her for driving traffic to my blog.

Wednesday, May 9, 2012

Too Dark, Too Light, or Just Right?

As I turned on the tv this evening, I saw a Nature episode on PBS chronicling the lives of two white white lion cubs in Africa. Individuals such as these indeed lead a difficult life; their inability to produce dark pigments leaves them not only highly visible to predators, but often not very attractive to potential mates. It's a rough life being different, something I think we can all identify with. However albinism isn't the only condition that can affect an animal's appearance. There are several ways an animal's coloration can vary, from not enough pigment, to too much, to poor diet.

Leucism, as seen in the lion above, is very similar to albinism, causing animals to be white or at least lighter in coloration. This is due to a lack of melanin, the pigment mostly (more on that later) responsible for an animal's color. The difference between albinism and leucism is that in albinism, the body cannot produce melanin and in leucism, melanin can be produced, but just isn't deposited normally on the skin, fur, feathers, scales, etc. Sometimes leucism just occurs in patches, resulting in what is referred to as a pied or piebald color morph.
Hey, who forgot to finish painting this snake? Nah, it's just a piebald ball python.

To tell an albino from a leucistic animal as in these American alligators, just look at the color of the eyes. Albinos have red eyes due to the lack of pigment--the red you see is due to the blood vessels in the eyes. Animals that are leucistic will still have colored eyes, but will be lighter than usual; commonly blue. 

Melanism is the opposite of albinism and leucism, meaning an animal has an over production of melanin, resulting in a color that is much darker than usual. Whereas animals that are lighter than usual often have a much lower survival rate because they stick out like a sore thumb in their environment, animals that are darker than usual may be at an advantage. One classic case of this is known as "industrial melanism", as seen in the peppered moth. 

Before the industrial revolution, peppered moths looked like this:
Yes, I promise there are two moths in this picture.

Their light coloration made for a spot-on match to lichen covered tree bark. Those moths that were too dark, ie melanistic, were quickly picked off by predators. However, once the industrial revolution began, pollution entered the air, killing off the sensitive lichens. This resulted in a role reversal: the light moths were now picked off the bare tree bark and the dark moths proliferated.
Dark moth: Yeah, who's laughing now?

Melanism became an adaptation, an advantage, in this situation. Other situations similar to these also occur, independent of human causes, for example a melanistic nocturnal animal better suited to hide in the dark night.

Remember how I said that melanin is the pigment mostly responsible for an animal's coloration? Well if you don't, I'm beginning to question just how closely you really read my blog. There are other pigments responsible for color, such as carotenoids. Carotenoids are produced in plants and are responsible for reds, oranges, and yellows in animals, mostly in birds and crustaceans. The only problem is that animals cannot produce their own carotenoids, so they must get it through their diet. The classic example that most people have heard about is the flamingo, which derive their pink from algae and invertebrates that they consume.

This good little ibis has been
eating all of his pellets.
Flamingos and other birds, such as the scarlet ibis, do not have the same foods available to them in captivity as they would in the wild. So how come they are still a vibrant pink? Dietary supplements! At the zoo I used to work at, we could always tell which scarlet ibises were good little birdies and ate their ibis food, and which preferred to steal from the diets of other species: the offenders were always a lighter shade of pink.

Many of our more familiar backyard birds rely on carotenoids for their brilliant colors: northern cardinals, goldfinches, and house finches, for example. 
The house finch is a common visitor to backyard feeders.

For house finches living in Hawaii, their diet has come to be quite different than their relatives living on the mainland, and as a result, their feathers look like this:
Aloha! Oh look, it's the NAI International Conference!

Whether it's albinism, leucism, melanism, or carotenoids, there are many ways in which an animal's appearance may vary. Some may be a disadvantage, while others may provide an advantage. Another fun factoid for you: black feathers are actually stronger than feathers of other colors! This is why if you look at birds that spend a lot of time soaring, such as gulls, white-pelicans, and white ibises, you'll see many of them have wings with black tips. Regardless of the reason for their colors, as humans we are always fascinated with any deviations that we see in an animal's color--an instance when being different is truly celebrated.