Fox vs. dog, no contest

Posted on Friday, April 30, 2010 by nosleepingdog

We were walking down a gravel road when, perhaps a hundred yards ahead of us, a grey fox crossed the road at a dead run, from a brushy area on the left of the road to a wooded area on the right side. The wooded area wasn’t very big; at its edge a long open grassy stretch began and continued to where we stood, and beyond.

Our mastiff Jack was off down the road instantly, turning into the woods where the fox had gone. Like us, he thought the fox would prefer the cover of the forest, or perhaps keep going away from the road, through the wooded area and up the steep brushy slope at the back.

Not so: while Jack remained in the woods sniffing around, here came the fox out of the trees and down the long open strip paralleling the road. He was completely exposed, and heading right toward us. Maybe he’d zigged and zagged a bit after entering the woods, to give Jack some scent to follow, but very soon he’d made a hard right to leave the confined area for a place where he could gain a lot of yardage on his pursuer.

By the time Jack followed his nose and reached the grassy area, the fox was long gone past us and out of sight; our exhilarated dog ran after him quite a ways before giving up. Then he came back to the woods to snuff up that interesting smell some more. I can imagine his satisfaction: finally, he had a visual sighting to go with one of the mysterious smells he’s found on our walks. And the fox, well, he proved his legendary cleverness once again.

Photo by dbriz

Lizard skin

Posted on Monday, November 2, 2009 by nosleepingdog

There are quite a few alligator lizards around our place, and one of them left a shed skin for us to find last month. Our lizards are probably the Southern Alligator Lizard, (Elgaria multicarinata). (See here for range map and basic info.)

[photo © Gary Nafis, from the californiaherps site]

The skin is complete, although in two pieces (ventral or belly view below).

The larger scales of the head

[photo © Gary Nafis, from the californiaherps site]

are clearly visible, or at least their clear covering is.

Also the legs, as they were arranged when the lizard wriggled and scraped its way out of the skin.

Here are the rear legs and vent.

And here’s a photo by Mark Leppin, in Northern Oregon, of the belly of a live alligator lizard:

The shed skin is turned inside out as the lizard peels it back over its head, by wriggling and scraping against whatever’s handy. Unlike most lizards, the alligator lizard sheds its skin in one piece (the one we found tore in handling), but it is like others in usually eating the shed. Depending on an individual’s health and rate of growth, it may shed every four to six weeks. Beforehand lizards and snakes may seek out water or damp places to help loosen the skin. The process is said to take only a few hours for those that shed in one piece.

Alligator lizards are insectivores but also take small eggs, snails, and probably anything else that they can find. The young are live-born, and we see them each summer––scarcely over an inch long, and very fast once they learn that everything bigger than they are regards them as lunch. The adults lose their tails once in a while, perhaps to snakes or other predators, and regrow them but the regenerated tails look stubby, not long and whiplike. Every dog we’ve had has tried to catch these creatures, without even coming close. My attempts to take pictures of them have all failed too, they’re just too wary and quick.

Views of a lion skull

Posted on Tuesday, October 27, 2009 by nosleepingdog

Recently I had the opportunity to photograph a lion’s skull. Since there seem to be few detailed photos of this subject online, I’m posting several here.

The ruler at the bottom is 3.5 inches (89mm) long. I don’t know the age or sex of this animal, only that it was an African lion. The ragged hole on top of the skull is a bullet hole; more about that later.

The large openings flanking the nasal cavity, and beneath the huge eye-sockets, puzzled me. Turns out they are the passageways into the eye area for the infraorbital nerve, artery, and vein (technically, each of these two openings is termed the “infraorbital foramen”). The infraorbital foramen is indicated by the arrow in the anatomical illustration below, from the University of Wisconsin’s digital collection of Veterinary Anatomical lllustrations.

In searching out what these openings were, I came across the information that Asiatic lions often have divided infraorbital foramina, with a bony bridge across the opening. Most African lions have the single open foramen seen in the skull I photographed. It is believed that the modern lion originated in Africa, and some researchers think that a severe population bottleneck at some point in the recent past of Asiatic lions may have allowed this variation to become common.

[]Thanks to Bibliodyssey for the post on these great illustrations.

The longitudinal grooves or clefts in the upper canines seem odd, though I found similar ones on another skull pictured online. Most of the lion skull images online were casts, replicas, and lack these grooves.

On the side of the lower mandible, insertion openings for nerves or blood vessels are clearly visible.

Turbinate bones and the air we breathe

Few skulls or replicas online show something I was especially interested in, the delicate turbinate bones within the nasal cavity. These are thin bony structures, with a rich blood supply, found in all modern warm-blooded animals. Here they show a complex scrolled shape that is marvelous to see.

The turbinates are also seen in the first photo; the close-up above is taken from a lower vantage point, looking farther into the nasal cavity.

What is the function of these unusual structures? The tissue covering the turbinate bones warms, cleans, and humidifies air as it is inhaled; the air exhaled from the lungs, which has picked up even more heat and moisture there, is cooled to reclaim moisture and prevent dehydration. The turbinate system also benefits the sense of smell. Humidifying the incoming air is necessary to “preserve the delicate olfactory epithelium needed to keep the olfactory receptors healthy and alert” (Wikipedia); the turbinates also increase the surface area of the inside of the nose and direct air upward toward the olfactory receptors. And, in humans at least, the tissues are what get swollen and obstruct our breathing, when we have allergic reactions.

The dinosaur connexion

The turbinates interested me because I remember reading speculation, in Digging Dinosaurs by palaeontologist Jack Horner, that dinosaurs were endothermic, warm-blooded––and he based this partly on indications that some skulls showed signs of turbinate bones (I don’t recall what exactly he described). However, that book was published in 1988, and it appears that subsequent researchers have failed to substantiate his suggestion. The delicate turbinate bones rarely survive as part of fossilized skulls; for example, none have been found in fossils of ancient birds’ skulls, even though the birds must have been warm-blooded. Some dinosaurs have thin tubular nasal spaces, as do present-day reptiles, and it is argued that those with narrow nasal cavities couldn’t have had turbinate bones. The question is not settled, but the current consensus seems to be that dinosaurs were not warm-blooded. For point-by-point summaries of the controversy, these seem good: The Evidence for Ectothermy in Dinosaurs (cold-blooded) and The Evidence for Endothermy in Dinosaurs (warm-blooded). Wikipedia considers some additional points in Physiology of dinosaurs.

Cause of death of this lion

The lion skull had been lent for a display in our local library, by the US Fish and Wildlife Service Forensics Laboratory in Ashland Oregon. It’s the only lab in the world devoted to crimes against wildlife, and I’ll say more about it in another post. The skull had been evidence in a despicable case: an individual bought up lions (they breed easily in captivity) from roadside zoos, put them in small enclosures and sold the right to shoot them. My grim theory is that the “hunters” were required not to shoot at the head, so that more shots could be taken at the living lion, before the highest-paying customer delivered the coup de grace in a shot to the top of the head. First, that would yield the most money for the scumbag, and second, it would have been very difficult to make this shot to the top of the head of a lion still standing.

At least the person running this was tried, and convicted with the assistance of the Wildlife Lab. Highly unlikely that he received a sentence I’d regard as sufficient, though.

A Cape Lion (Panthera leo melanochaitus, now extinct) in a drawing of the Dutch artist Rembrandt Harmenszoon van Rijn. Circa 1650-52. Location: Louvre, Paris. Source, Wikimedia Commons.

Visit to a California Eucalyptus grove

Posted on Saturday, August 15, 2009 by nosleepingdog

Growing up in Northern California, I always had a special fondness for the eucalyptus; various species have been planted there, mostly as windbreaks. They grow fast, are evergreen, and haqve fragrant leaves and varicolored bark that peels away in great strips.

So last week as we headed home from Sacramento, up I-5 to Southern Oregon, I wanted to stop and get close to some eucalyptus again. We left it a little late, and settled for a planting at a rest stop, on the northern edge of where eucalyptus flourish. These were not as densely planted as many groves, but then you can appreciate the individual trees more.

These trees were afflicted with scale, which you can see as small white spots on the narrow leaves.

Bark patterns are always fascinating; like the madrones of Southern Oregon, eucalyptus trees present masterpieces of natural form wherever you look.

Wildlife

You can’t expect to see much in 20 minutes, during the hottest part of the day, among trees next to a freeway rest stop, but we found a bit.

In the picture below, a woodpecker’s work can be seen at the top.

We found traces of some sort of beetles under peeling areas of thick bark, and these are probably what the bird was hunting.

At night, other insect hunters emerge; at mid-day they were sleeping high in the trees invisible to us, but one who had died lay beneath a roost tree. (Traces of droppings, along twenty feet of the tree’s trunk, indicated the presence of multiple individuals.)

We did not examine him or her, and I’m not sure what the species may be.

A good guess would be the little brown bat, Myotis lucifugus: it’s very common, it is the right size and color, and has small dark ears as this one does. Or maybe California Myotis (or “California Bat”), Myotis californicus. I am really just guessing––one source says there are 24 species of bats in the state of California. The small ears and lack of a “leaf-nose” structure do rule out a few candidates.

The butterfly we saw and photographed we do have an identification for, though: the Common Buckeye, Junonia coenia:

I didn’t recognize it, and located a useful list of California butterflies with links to photos and information on each species. Then it turned out that Dan knew what it was all along, but it was fun to look through butterfly photos and have the Eureka! of seeing it. Maybe I will remember it better that way. The Common Buckeye probably isn’t resident where we saw it; the Butterfly Site says it lives along the coasts as far north as Central California in the West and North Carolina in the East and that:

Adults from the south’s first brood migrate north in late spring and summer to temporarily colonize most of the United States and parts of southern Canada.

That’s a lot of traveling for this tiny seemingly fragile creature.

Eucalyptus seedpods

I wanted to collect some seeds to grow at home, and had in mind the seed pods that are up to an inch long and look like this (source of drawing), though the ones I wanted are silvery-grey in color.