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Archive for the ‘wildlife’ Category

How did Komodo dragons survive?

dragon eats goat

Komodo dragons are the world’s largest lizard.  They are supersized monitor lizards that first evolved in Australia four million years ago.  One million years ago they arrived on the Wallacea Islands, where they fed upon a dwarf species of elephant. That elephant went extinct 50,000 years ago. The mainland Australian population of these lizards went extinct around the same time as those dwarf elephants.  The main prey of Komodo dragons now consists of introduced ungulates that arrived on those islands between 7,000 and 10,000 years ago.

That means Komodo dragons spent 40,000-43,000 years without large terrestrial prey sources, and if that is the case, how did they survive?

Well, a new paper in the journal Global Ecology and Conservation attempts to answer that question.

Apparently, Komodo dragons are an odd mix of the best ectotherms and the best of endotherms.  As ecotherms, they have the ability to rely upon limited food resources, and it just so happens that the oceans around their last island redoubts are quite diverse marine ecosystems. So the dragons would have plenty of marine food that they could scavenge. They also have the ability to reduce their growth rates to compensate for the lack of large prey species on the island, a trait that has been shown in the subfossil record. Remains of dragons that date to these lean millennia show that dragons were significantly smaller then than they are now.

Also, unlike most ectotherms, Komodo dragons, like virtually all monitor lizards, have the ability to adjust their behavior and try new food sources. When tourists scared off the ungulate prey of Rinca Island, the dragons simply started hunting macaques and raiding scrubfowl nests.

Further, the dragons could also live nicely as cannibals. Smaller dragons get eaten by the larger ones, and because the dragons produce far more offspring than could ever reproduce, the excess dragon young could have fed the adults quite well.

Humans also never really thought of these arid and semi-arid islands as good places to set up large scale agriculture, and because these islands were also devoid of native prey species, humans were not widely using them as places to hunt until deer, buffalo, and pigs were introduced.  When humans did settle the islands, there were enough dragons in the population that had “shy personalities” that kept them from causing conflicts with humans. These “shy” dragons are disproportionately female, and they could have passed these more retiring traits onto their offspring, which is why Komodo dragons are not killing people left and right. People likely killed off the bolder males when they first began to settle these islands, and in a species were the sex ratio tends to be biased in favor of males, any trait that would have increased a female’s survival would have definite consequences in the population genetics of the species. That means that the “shy” trait could have easily become expressed in the population, simply because humans would have low tolerance for aggressive behavior.  Dragons today generally avoid people.

Finally, females of this species are capable of reproducing via parthenogenesis. Males in this species are larger, and if conditions became so bad that all the large males died off, some of the females would still be able to reproduce anyway.  Because of how the lizards’ sex chromosomes work, they can only produce male offspring when they reproduce this way, which could be a way to restore males to a population that lost them through a lack of food resources.

Komodo dragons were once quite widespread across Australia and several nearby islands, but now they exist only on the islands of Wallacea. These islands are named for Alfred Russel Wallace, a co-discoverer of evolution by natural selection. Wallace noticed that the native animals of Sunda, which is the Malayan Peninsula and the Malayan Archipelago, are fundamentally different from the native animals of the islands just to their east.  The animals of Sunda generally have an Asian origin, while those of the islands to the east are more of Australian origin. The line between these islands is called the Wallace Line.

The dragons of Wallacea are of Australian origin. Their current main prey sources are all most of Asia origin. So in the Holocene, humans broke down Mr. Wallace’s Line, and the dragons grew back into their larger form. This larger dragon was the same one that hunted the megafauna of the Australian mainland, playing second fiddle to only the larger monitor called megalania (Varanus priscus).

I have often wondered what it would have been like to have seen the mammoths that lived on Wrangel and St. Paul Islands. These mammoths were the last survivors of a species that range over much of Eurasia and North America until 10,000 years ago, but they continued to survive on St. Paul Island for 5,600 years. They died off on Wrangel Island only 4,000 years ago, and they only died out because of a weird genetic mutation similar to the rex mutation in rabbits that made it harder for them to insulate their bodies on that cold island.

But by several accidents of their biology, the Komodo dragons have not undergone the same fate. They still exist as a relict population.

We have a hard time living with large predatory animals. They tend to inconvenience our way of life pretty badly. However, the people of these islands do benefit from the dragons. They attract a lot of tourists and their dollars. There is real economic benefit to having such creatures roaming about.

But I don’t know how long this can last.  Because the dragons have these shy behaviors where they avoid humans, increased tourism on these islands could greatly stress them, making it harder for them to thrive and breed. These concerns came at about the same time of a mass arrest of an animals smuggling ring that had 40 dragons in its possession, which has led the Indonesian government to ban tourists from coming to Komodo Island in 2020.

If the islanders cannot make money from tourists, though, it is very likely they will try to make some money selling the dragons to smugglers, and if authorities are not on top of things, the Komodo dragon might not survive the Anthropocene.

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Mule deer dreams

mule deer stott

One of my dreams is hunt mule deer in the West. I don’t care where in the West. I just want to go out on into that big country, wander around the rocks and cliffs and sage brush, climb out onto a high vista, and glass the scenery for antlers.

I am from the land of white-tails. White-tails are the ultimate habitat generalists, and in “settling” and “civilizing” these Eastern lands, we have create a paradise for them. They can wander the forest devouring acorn after acorn, and they can grow fat and glossy in the fields of soybeans and corn.

The mule deer is a different animal. It migrates from higher elevations to lower ones. It likes much more open forests and grasslands and sagebrush steppes.

Current taxonomy says that the various forms of mule deer and the two subspecies of black-tailed deer represent a single species, but the black-tails are creatures of the Pacific Coast forests. They are different entity in my mind, though I’m sure the deer exchange genes where one form’s range runs into another without any consideration of human classification.

These arid and semi-arid land mule deer, though, are what has me fascinated. The mature bucks are rather large and impressive, more so than the equivalent white-tails. But I do not think of them so highly because they are larger. I think of them so highly because they have a Western mystique. They are not such habitat generalists in the way white-tails are.

They are beings of a more specific landscape, a landscape that is under threat in part because oil and gas development, housing speculation, and overgrazing by livestock are taking their toll. The spread of cheatgrass, which grows into lovely fire tinder, is also to blame. The fires that spread from its stalks wipe out the sagebrush, which the mule deer rely upon to feed them through the winter.

So the white-tail basks in the glory that is our civilization, as the mule deer continues to retreat and withdraw from it. And in this, I find their true appeal.

I hope that when I will get a chance go West on a mule deer hunt before it is too late. I can see a time when the deer will become so hard-pressed that hunting opportunities will be curtailed, even abolished. I hope that we will be wise in our understanding what is happening to these deer before they lose the range and forage on which they so clearly depend.

To hunt mule deer is to go nearer to the wilderness, perhaps even into it.  It is an odd little romantic dream of mine at which I’m sure some Westerners will laugh.

But these deer still exist in the sage and rocks and grasses. They are the setting sun, casting away beyond the Western horizon, beckoning me across the continent to cross the prairies and the mountains.

And someday, I hope to. Before it’s too late.

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marsh rabbit

One of the most interesting aspects of North American wildlife is the wide diversity of rabbit species. The most common rabbit species in the Eastern and Midwestern US is the Eastern cottontail (Sylvilagus floridanus), but it only one many North American rabbits.  The genus of cottontails, Sylvilagus, includes many regional and specialized forms. In the Allegheny mountains, there are Appalachian cottontails (S. obscurus), and in parts of New England and New York State, one can find the New England cottontail (S. trasitionalis).  In the West, we have desert cottontails (S. audubonii) and the mountain cottontail (S. nutallii) in the interior, and the brush rabbit (S. bachmani) along the Pacific coast.

However, those are pretty banal bunnies. Over the past week or so, though, I’ve seen the video clip from the CBC showing a swamp rabbit swimming strongly to evade predators, So I thought I would take some time to talk about our “water rabbits,” the two species of cottontail have evolved to live in the Southeastern swamps and marshes.

From Southeastern Virginia to Florida and as far west as Mobile Bay, the short-eared marsh rabbit (S. palustris) lives makes its home among fresh and brackwater marshes and swamps.  They live among the cattails and mangroves and thickets of black gum and magnolia. They tend to be smaller than Eastern cottontails, which can also appear in similar environments, and their tails are usually shorter and are almost never fully white.

The swamp rabbit (S. aquaticus) by contrast is the largest cottontail species, averaging double the mass of an Eastern cottontail.  It is much larger than the marsh rabbit. The only states where both of these species are found are South Carolina, Georgia,  and Alabama, but there isn’t much range overlap. This rabbit likes cypress swamps and lowland river floodplains. They range as far north as southern Illinois and Indiana, but they are particularly common in the Mississippi Delta.

These two species are considered sister taxa, and these two rabbits are placed in the subgenus Tapeti. This subgenus includes mostly cottontails from Mexico on south, and these two water rabbits are the only two members of these subgenus found in the United States. This classification has been determined through a limited mitochondrial DNA study. 

Of course, I would like to see more studies of the various cottontail rabbits’ genomes, but this classification is the only one currently accepted.

I should note that one subspecies of marsh rabbit (Sylvilagus palustris hefneri), which is found in the Lower Keys of Florida, is considered an endangered species.  It is named for Hugh Hefner, whose corporation donated a substantial sum to research this rabbit.

This rabbit is vulnerable because of predation by feral cats, as well as other invasive predators, such as boa constrictors and fire ants. Invasive plants have also destroyed the undergrowth that these rabbits use to hid from their predators. Many of these rabbits are also victims of traffic.

Maybe this rabbit would get better attention as an endangered species if conservationist played up its connection to Hugh Hefner. We could call it “The Campaign to Save the Real Playboy Bunny. ”

The swamp rabbit has a following among beagle houndsman in much of its range, and these rabbits are taken as monster trophies in much the same way that Eastern deer hunters who have hunted white-tails their whole lives will go west in search of a monster mule deer.  The old way of hunting both swamp and marsh rabbits was to burn them out of their marsh grass hideouts, but wildlife management agencies regulate the hunting of both species.

So when you see that clip of the swamp rabbit swimming think of both of these rabbits. They are amazing creatures, perfectly adapted to living near water and using their strong swimming abilities to evade their most aggressive predators.

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coyote killing cat

An analysis of coyote feces from various parts of Southern California has revealed something rather shocking.  Yes, coyotes are coming into people’s lawns and cultivated gardens and eating lots of fruit, but the analysis revealed that cats comprise 20 percent of their diet in urban areas.

This is in direct contradiction of Dan Flores’s contention that coyotes usually just kill cats because they are competitors and leave their carcasses to rot in the sun.  He makes this claim in both Coyote America and made it again on Joe Rogan’s podcast.   If cats comprise 20 percent of their diet, coyotes clearly are targeting them as a prey species.

If one thinks about it carefully, cats are about the best meat a coyote can get in most urban environments.  Where there is civilization, there are many cats. and when you’re  a 25-30 pound coyote, an 8-10 pound cat would sustain you for some time. Most indoor-outdoor cats somewhat fat and usually lack any skills for living in anything like “the wild,” so of course, coyotes are going to target cats.

One of the authors of the new study is Justin Brown, who also appeared on Joe Rogan’s podcast after Dan Flores. I much preferred the discussion with Justin Brown, who was polite and knowledgeable about urban carnivorans, but it was obvious that he disagreed with some Flores’s airy-fairy ideas about coyotes.

Indeed, I think the reason why Flores’s book about coyotes gets so much attention is that it does present the coyote in a way that sanitizes it from what it really is. Coyotes are predators. They do kill sheep. They do kill dogs. They do take cats. They have killed people, including fully adult Taylor Mitchell in Nova Scotia.

These facts should not make us want to exterminate coyotes. Indeed, when someone says they want to do such a thing, I wonder if they might have come up with a more realistic goal in life like blowing up the sun or draining the ocean.

We err when we turn coyotes into terrible predators that deserve only death, but we also err when we turn them into the prick-eared Labradors of nature.

We should admire the coyote as the one of those Anthropocene wolves, a sort of North American super wolf that has thrived in spite of our attempts to eradicate it from the landscape. We have to adjust our behavior to live with them. Not letting cats go outside is probably a good idea, not just for their own welfare but for the welfare of lots of native species that cats target in their hunting forays.

We also need to understand that livestock producers must deal with coyote depredations.  Yes, we can encourage them to use nonlethal methods.  However, we shouldn’t be as judgmental of someone killing the odd one to protect livestock.

So yes, we now have evidence that coyotes are targeting cats in urban environments. If we love our cats, we’ll keep them inside. Cats don’t need to be outside to be happy, and they will never become a coyote’s breakfast if they stay where the Old Song Dog won’t be able to catch them.

This shouldn’t have been much of a shock. A similar study in 2009 in Tucson, revealed that 42 percent of an urban coyote’s diet consisted of cat meat.

The discrepancy in these two studies probably comes from the fact that coyote predation upon cats has become much better known by the public in the past decade, and Californians probably have at least heard of the studies that show how many birds, small mammals, reptiles, and amphibians cats kill every year.

So yes, if you let your cat outside, you are taking risks. Some people think it’s worth it.  That’s okay, but don’t blame the coyotes for doing what comes naturally. They are trying to survive in an human dominated world, and you’re providing them with an easy, nutritious prey source.

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skunk

With declining populations of pheasants and waterfowl plaguing South Dakota sportsmen, the state has instituted a new bounty program aimed raccoons, badgers, striped skunks, red foxes, and opossums.  A household can earn up $590 from trapping and hunting these animals during the new bounty season, which runs from April 1 through August 31.  The state is paying $10 per tail of these predators, but it will stop once the bounties pay out $500,000.

This state, which relies heavily upon nonnative ring-necked pheasants as a game animal to attract sportsmen, is essentially trying to turn the whole state into English gamekeepers.

I’m not opposed to controlling nest predators, but I’ve always had a problem with bounties. Bounties are easily defrauded. My grandpa used to tell the story of his friends in Ohio, one of whom was a city cop, who would drive to West Virginia and shoot crows. They would take the crows back across the river and present them for the bounty payment, and no one would know.

Controlling nest predators is important to promoting gamebird population, but humans can only do so much.

The predators that the state is targeting are mostly ones that have only existed there since colonization and settlement. Raccoons didn’t live in the Upper Midwest or the Great Plains until barns spread everywhere. Opossums were originally restricted to the Southeast.

The pheasant is entirely introduced. The first successful introduction was in 1908, and the state promotes that bird to the hilt.

So in this new world, there really isn’t any wild that is let go. This is the world of the English gamekeeper managing wildlife for gamebirds on the American marshes and prairies.

It’s not really all that natural. But it is the new world of wildlife on this continent.

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portuguese man o' war

On our recent travels to Florida, we stopped at a dog-friendly beach at Jupiter, and we came across this Portuguese man o’ war.

This thing is not a jellyfish.  It is a colonial organism called a siphonophores, and as a colonial organism, it consists of four animals called polyps.

The tentacles can leave a nasty sting, so we kept the dogs away. And we weren’t touching it.

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The Biting

great white in the surf

The shark was a torpedo with teeth. She swam the seas in search prey. Her preference was dolphin meat, and she often pursued her quarry into the surf zone.

Bottlenose dolphins are wiser creatures than the great fish. They knew about her presence often before she knew of theirs. All she could do is slip around where the dolphins might be hunting and hope that one slipped up.

On this day, she was working them close to the crystal sand beach. Every time, she thought she might get the drop on a dolphin, another dolphin would raise an alarm and they would swim around her, mobbing her, almost taunting her, until she slipped back into the depths.

Hunger was starting to take its toll, and now she began to work the surf once again.  Her black eyes noted something whitish pink and smooth suspended in the rushing water.

Her shark brain asked “Could that be something to eat?”

And she swam over and tested the pink thing in her mouth. When she bit down, the blood gushed everywhere. But the meat had no fatty taste to it, so she let go when she felt the quarry slap her.

She then swam back into the depths, scenting the water again for that delicious odor of dolphin.

What she had not known on this first sultry day of May on this desolate beach on North Carolina’s Outer Banks is that she had bitten a person, the son of a wealthy corporate lawyer.

The young man screamed in terror. He had been wading alone in the surf, hoping to make communion with the local pod of dolphins. He felt that thing brush up against him and then the hard pressure of the bite. Then the flowing of red blood.

His right butt cheek down to his right thigh was hanging open and bleeding, and how he managed to swim with that much blood gushing from his body no one really could fathom.

He made it to the foamy line where the white water splashes on the crystal sand.  He landed hard on the compacted earth and groaned in agony.

His girlfriend found him five minutes later as she came down to walk their obese golden retriever on their private beach. He was sent to the hospital. Hundreds of stitches and blood transfusion were his treatment.

In week, he knew that he’d met the sea monster and had lived.

The biting had happened. The great torpedo fish claimed a victim without knowing anything other than she’d bitten into something quite disgusting.

And she was two hundred miles away when the young man’s family finally got together and took stock of the situation.

The father believed he should sell the beach house and buy a nice cabin on a quiet mountain lake, were the largemouth bass rose in the April sun and the ducks sat fat upon the shore.

The mother believed they should keep the house at the beach, but under the condition that no one ever go into the water deeper than the waist.

The young man had no thoughts on the matter. He had not expected to be bitten. It felt like something so random, so strange, that he didn’t know what to think of it all.

Yes, the bite had harmed his hide. But he was going to live, and although he felt physical trauma, he was oddly at peace with the whole thing.

The shark had bitten in error, not in malice. He had seen enough nature documentaries to know this fact, and the odds of it happening again where somewhere in the winning the lottery category.

But the victim can try to reason with those who see the aftermath and still not be able to assuage their concerns.

The father had called up the department of fisheries in hopes that he a posse could be assembled to wipe out such large sharks from the waters. When he found that the great whites were protected in these waters, he was filled with bellicose anger.

He paid for that spit of sand, and now, the government was telling him he could not protect his property and family from sharks?

He called everyone he knew in the world of government. They listened as intently to him as they would anyone with potential to flip out some campaign money, but nothing was done.

The laws were the laws, and what’s more, every single expert told him that the shark was long gone.

Man has this odd tendency to take personally the banal violence of nature. The young man had come to the realization that this was not a personal attack at all, but just an accident of predation. The father never could accept this reality.

He put the beach house up for sale, but the sell did not go through until the July of the next year.

The young man didn’t tell his father what he was going to do, but on the last weekend hte house remained in his family’s hands, the young man went to the beach. He slipped on his rash guard and wandered into the surf.

He hoped to make final contact with the dolphins. Yes, that was certainly a goal.

But he also wanted to make peace with the sea monsters, the ones that still stubbornly hold onto their domains despite ourselves.

The dolphins came at high tide to cavort among the surf and hunt baitfish. He felt their echolocation against his skin once again. He felt at peace in the saltwater.

And he felt the true humility of a human in the sea. The ocean suffers the onslaught of our civilization in such horrific ways, but it still exists undominated, uncontrolled.

And that briny wilderness is an affront to those who worship in our domination, but it beguiles those who see it as the last redoubt of unblemished life.

And the young man felt that sublime beguilement and felt the warm water rushing around him.

And he then left the sea to the ancient struggle of dolphins and sharks, which he hoped would go on long past his mortal existence as a man on this earth.

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