Monday, May 27, 2019

Last camping trip on planet Crematoria

It was a beautiful weekend on the Peace River
if you like being swarmed by no-see-ums, flies, and mosquitoes
while sweating in +90ยบ temps.
I do NOT.
But I've had next to no digging time this season and I wanted to close out a site that's been so good to us for over 2 years. We might've spent 2 more seasons here but Hurricane Irma put an end to that.

The first thing I wanted to see on this trip
was whether or not the sapling clothes rack I made last year had survived the summer floods. Amazingly, one side was still standing and the cross bar was still threaded through some tree branches where I'd left it.
Still good for drying a couple of items.

I always get a little sentimental when I close out a productive digging site
because I've spent hundreds of hours there, absorbing everything about the scenery, the water, the invisible terrain of the river bottom.
It also means I'll have to start prospecting again.
Insert frowny face here.
All good things come to an end...

It wasn't a total wash; we found a few odds and ends.
Glyptodont Heaven is no more.
I really, REALLY thought I would find one more glyptodont scute but only this fragment turned up in my screen after 2 days of digging. One excellent giant armadillo scute was probably my best find for all of the effort.
I like my little green Canada Dry bottle. It was a nice break from the constant parade of Bud Light bottles that we dig up.  I also found an old Tab can. I knocked back of lot of those in my teens.
This is a piece of ear bone but I have no idea from what animal. I like the delicate little channels found in fossilized ear bones.  This one is good enough to find a new home in the Ear Bone Jar.
Yes, I have an ear bone jar. Only vaguely creepy.

Small sharks teeth. 
Small numbers of small sharks teeth.

Little goodies including a sea urchin spine, "swollen fish vertebra" (whatever that means), alligator tooth, sloth osteoderm, garfish scale, fish jawbone, and snake vertebra.

A piece of fossilized wood.

And lots of turtle.
Always lots of turtle.

Goodbye, dear sweet primitive campsite, goodbye glyptodont heaven, and goodbye to the Snag
where we found everything from the remains of a wrecked boat to the teeth from giant ground sloths and dire wolves.  On to the next great thing!

And for your further reading pleasure, here's some information about fish jaws straight from Wikipedia:

Most bony fishes have two sets of jaws made mainly of bone. The primary oral jaws open and close the mouth, and a second set of pharyngeal jaws are positioned at the back of the throat. The oral jaws are used to capture and manipulate prey by biting and crushing. The pharyngeal jaws, so-called because they are positioned within the pharynx, are used to further process the food and move it from the mouth to the stomach.
Cartilaginous fishes, such as sharks and rays, have one set of oral jaws made mainly of cartilage. They do not have pharyngeal jaws. Generally jaws are articulated and oppose vertically, comprising an upper jaw and a lower jaw and can bear numerous ordered teeth. Cartilaginous fishes grow multiple sets (polyphyodont) and replace teeth as they wear by moving new teeth laterally from the medial jaw surface in a conveyor-belt fashion. Teeth are replaced multiple times also in most bony fishes, but unlike cartilaginous fishes, the new tooth erupts only after the old one has fallen out.
Jaws probably originated in the pharyngeal arches supporting the gills of jawless fish. The earliest jaws appeared in now extinct placoderms and spiny sharks during the Silurian, about 430 million years ago. The original selective advantage offered by the jaw was probably not related to feeding, but to increased respiration efficiency—the jaws were used in the buccal pump to pump water across the gills. The familiar use of jaws for feeding would then have developed as a secondary function before becoming the primary function in many vertebrates. All vertebrate jaws, including the human jaw, evolved from early fish jaws. The appearance of the early vertebrate jaw has been described as "perhaps the most profound and radical evolutionary step in the vertebrate history". Fish without jaws had more difficulty surviving than fish with jaws, and most jawless fish became extinct.
Jaws use linkage mechanisms. These linkages can be especially common and complex in the head of bony fishes, such as wrasses, which have evolved many specialized feeding mechanisms. Especially advanced are the linkage mechanisms of jaw protrusion. For suction feeding a system of linked four-bar linkages is responsible for the coordinated opening of the mouth and the three-dimensional expansion of the buccal cavity. Other linkages are responsible for protrusion of the premaxilla.


Wednesday, May 15, 2019

An Abbreviated Season

It's gonna be a SHORT fossil season for me,
due to all the rain,
so I'll make this a long post in the spirit of balance.

If you're anything like me, 
you're getting a little bored of seeing postings
from all these people finding complete mastodon and mammoth teeth.
(yawn...)
Allow me to mix it up a bit.
Take a look at this beauty...
Oh yeah...that's right...
100% pure rodent.
And the best part is, you actually have a fairly decent chance of finding one just like it or better.  
Just be sure to use your 1/4" screen and wear those groovy looking magnifying glasses while you sift the gravel.

It was so nice to finally have a weekend free 
where the rain had backed off for a few days and Pam and I were able to meet up for some much needed river time.
We're absolutely glowing!

I managed to find a few little items of interest and it was a gorgeous day on the river.

I'll never say, "No," to a whole tapir cap.

A really excellent dolphin periotic ear bone.

A handful of scutes from glyptodonts and giant armadillos.

Turtle and tortoise material.

Those strange little osteoderms that apparently came from the skin of certain species of giant ground sloths.  This is my entire collection. 
Only the 2 on the right came from this recent visit to the Peace River.

A glossy fragment of a mastodon tooth.
Who needs the whole thing anyway?! Right?!

Some more rodent material, this time in the form of a chunk of capybara tooth.

Crystalized sea urchin spines.

Tiny stuff including garfish scales, barracuda tooth, stingray spine, and bone fragment.

One horse tooth and plenty of horse tooth fragments.

Fossilized deer jaw fragment with a couple of teeth.

A good haul of small shark teeth.  I find these using a 1/2" screen and it's not easy but, as you know if you've read this blog before, I don't have the patience for a 1/4" screen.

Soooo, no fireworks or anything too exciting
but still better than a kick in the head.

And now allow me to plump up the word volume of this posting by giving you some information on the deer population of the United States from actionbioscience.org.
White-tailed deer (Odocoileus virginianus) rank among the most charismatic wildlife in North America. Emblematic of the countryside, a deer sighting signifies we left the busy city behind. Spotted fawn sightings evoke images of Bambi, and such sightings serve as harbingers of summer. In recent decades, deer numbers have grown. In some places, deer are so numerous that they are degrading their own habitats and causing conflicts with people. Consider:
The U.S. is home to about 30 million deer.
  • There are an estimated 30 million deer in the United States today. Under optimal conditions, deer populations will double every two years.1 They can reach densities of over 1 deer per hectare (100 deer per square kilometer).2
  • Over 10 million people spend nearly $6 billion to hunt deer in the United States each year.3 Over 6 million deer are killed during the hunting season, based on state agency records. If each deer provides an average of 22 kg of meat, this amounts to 132,000 metric tons. An estimated 12 million fawns are born a few months after hunting season.
Car collisions with deer numbered over 1 million in 2008.
  • In 2008, over one million deer collided with cars and motorcycles in the United States. According to estimates by the Insurance Institute for Highway Safety, this resulted in the death of 150 people, injuries to 29,000 others, and an estimated $1.1 billion in vehicle damage.4
  • An average deer will eat nearly 500 kg of vegetation each year.5 The entire population of deer in the United States will eat the equivalent of 15 million metric tons of vegetation per year, which is greater than the combined weight of all aircraft carriers in the U.S. Navy! 
  • One recent study of 13 northeastern states revealed deer caused $248 million damage each year to agricultural crops, nurseries, and landscaping.6
  • In parks and other natural areas, deer consume wild plants. Over time, spring wildflower displays diminish. Plants highly prized by deer decline or disappear entirely. In some places, deer are responsible for the disappearance of over half of all plant species—in just a few decades.7,8
  • Deer play a role in the transmission of tick-borne infections to humans, including Lyme disease.9
It is quite possible that deer provide more economic and aesthetic benefits to people than any other mammal in North America. At the same time, they may cause more harm and injuries to people than any other North American mammal. Confronted with the mixed blessing of white-tailed deer, wildlife biologists are broadening the scope of the discipline of wildlife management. 
Moose, elk, and other types of deer are also overpopulated.
The problems posed by white-tailed deer overabundance are by no means unique. There are several cases of overabundant populations of moose (Alces alces)10 and elk (Cervus elaphus)11 in parts of their native range in North America that lack native predators. Sika deer (Cervus nippon) have caused extensive damage throughout parts of Japan.12 Both native and introduced deer have caused extensive damage to woodlands and plantations throughout Europe, and introduced deer and elk have reshaped temperate rainforests in Canada, Chile, and New Zealand.13

The fall and rise of white tails in America

White tails were nearly extinct 100 years ago.
With an estimated 30 million white-tailed deer in the United States today, it is difficult to believe these animals nearly became extinct just over a century ago. The United States was undergoing a profound transformation, facilitated in part by a rapidly expanding railroad network. In some ways, environmental changes benefited deer. The bounty hunting of gray wolf (Canis lupus) and cougar (Felis concolor), and the subjugation of indigenous peoples, reduced predation pressure on deer. At the same time, market hunting, weak enforcement of game laws, and habitat loss conspired to drive deer to dangerously low numbers by the late 1800s. By the early 1920s, deer were extinct in some states—including Kansas and Indiana. They were endangered in many others.14
Active conservation efforts, including hunting restrictions, conservation law enforcement, predator control, game refuge creation, and deer reintroduction were used to restore endangered or extirpated deer populations. These conservation efforts were initially financed by governments and were later financed in part by deer hunters through state licensing revenues. Deer populations responded by increasing 1-2 orders of magnitude throughout their range over the next 100 years. Even today, the recovery of white-tailed deer is a premier example of successful wildlife recovery and management in the United States.15
Wildlife and hunting measures aided the deer’s recovery.
Initially, deer hunters and state wildlife agencies were partners in this recovery. Hunters provided funding and political will, while the state provided increasing numbers of deer. Over time, deer populations grew to the delight of both hunters and state wildlife agencies15; however, new stakeholders emerged: 
  • Animal rights groups objected to sport hunting. 
  • Farmers wanted more control over the deer on their properties that were eating their crops. 
  • Park managers wanted more say in the numbers of deer on the lands they managed. 
  • Public health officials expressed concern about the relationship between deer abundance, tick-borne diseases, and human health.16
Such disparate views confounded wildlife managers. Serving the public became a lot harder when there were multiple competing interests.17
Recreational hunting is a major way to keep deer numbers down.
Historically, deer densities varied from 2-6 animals per square kilometer (km-2).18 Today, white-tailed deer inhabit a range of natural, semi-natural, and anthropogenic environments, and they can reach densities in excess of 40 km-2, in the absence of hunting or predation.19 Even where deer are managed through sport hunting, populations typically exceed 10 km-2, even though negative impacts to vegetation and fauna become apparent at lower densities.20 Recreational hunting remains the primary mechanism that limits white-tailed deer throughout most of their range.21 This leads us to an obvious question: why are deer densities increasing? There are several reasons:


Nature’s deer predators have disappeared.
  • Absence of predators.22 Historically, wolves and cougars preyed on deer year-round. Wolves and cougars are now absent from most of the eastern United States. Other predators of deer—black bears (Ursus americanus) and coyotes (Canis latrans)—typically prey on fawns but not adult animals. Additionally, unlike wolves and cougars, deer are not their primary prey item. 
  • Declining numbers of hunters.21 The number of hunters in the United States has been declining since the 1970s. Fewer hunters in the woods during deer season will translate into larger deer populations over time.
  • Expansion of “no hunting” zones.21 Where deer hunting is prohibited, deer populations can grow and spread to surrounding areas. Parks, open green space, small towns, and in many cases, suburban developments are de facto deer sanctuaries. In rural areas, private landowners that once welcomed deer hunters are increasingly turning them away, due in part to legal liability concerns.
Vegetation grown by humans is gourmet food for deer.
  • Habitat changes. The agricultural fields and pastures, orchards, fertilized and well-watered suburban landscapes, as well as parks provide a greater abundance of high quality food for the deer than the eastern deciduous forest they replaced. Greater habitat productivity leads to greater numbers of deer.23
These factors combined create conditions favorable for the maintenance of high deer densities for the near future.