Spinning Tales About Claws, Hooves, and Nails

What determined which creatures now display claws, hooves, or nails?  Evolution!  It provided for specific needs.  Originally, some creatures had claws, and their descendants still prevail with claws.  Meanwhile, species desperate to run from predators emerged from claws to hooves.  Primates progressed by developing grasping hands and feet tipped with nails.  These three appendages contain keratin, a key structural protein.

Red-tailed Hawk Talons

Many wild beings are equipped with claws—birds, reptiles, and mammals.  Comparable to nails, claws protect the digits.  Similar to hair, claws grow, cease, and restart.  For birds, claws furnish holdfasts.   Talons (sharp claws) enable raptors—like eagles, hawks, and owls—to prey.  Reptiles, such as alligators, may utilize claws to uproot vegetation.  Though



snakes are clawless, boas and pythons, primitive reptiles, exhibit remnants of hind limbs with spurs (claw-like projections) on the sides of their waste openings.  These spurs are employed for reproduction.  As for mammals, Florida black bears flaunt hefty, curved claws which facilitate climbing while chasing humans up trees, after reportedly sprinting up to 35 miles per hour.  And they are fearless!  A black bear, accustomed to roaming and feeding in Seminole County neighborhoods, was captured and killed in January, 2015.  Its record weight:  740 pounds.  By the way, remember when bear claws were pursued for ornaments?  Nowadays, bear claws are relished as pastries!  Finally, what about lobster or scorpion claws?  They are actually pincers (chelae). 

Mole Claws for Digging

Squirrel Claws for Climbing

Hooves (or hoofs) are enlarged, weight-bearing toenails.  Mammals equipped with hooves are classified as ungulates.  Most even-toed ungulates, such as deer and pigs, have two main hooves on each foot—together identified as a cloven hoof.  Two smaller hooves, dewclaws (false hooves), are situated slightly up the leg of most cloven-hoofed animals.  Larger dewclaws, as in deer, contact the ground for jumping.  Variation occurs in some species—equids, such as horses, have just one hoof on each foot.  Hooves grow continuously.  Wild ungulates trim them by sufficient ground contact.  On the other hand, domesticated horses are not as active and generally require maintenance—akin to human toenails needing a pedicure.  One can imagine soaking those huge hooves prior to trimming!

Regrettably, natural habitats are shrinking.  Animals commonly explore yards for nourishment.  Homeowners may detect hoof prints molded in upturned sod or under stripped hibiscus trees, including a few more tunnels clawed by the armadillos.  Still, these wild ones must survive!

-  photos by Brett Pigon

Spinning Tales About Eggs

Various creatures reproduce by laying eggs.  They are oviparous species including birds, reptiles, fish, amphibians, insects, arachnids, mollusks, and a few mammals (monotremes)—the duck-billed platypus and four species of spiny anteaters.

A bird egg is commonplace and often distinguishable by pigmentation, shape, location, markings, gloss, and size.  Composed of calcium carbonate, it may be white, or, if laid by a passerine (perching bird), it is usually colored.  Customarily, an egg is oval and somewhat pinched at one end from compression inside the mother—thus, it safely rolls in a circle when discharged.  Moreover, a cliff-nesting bird produces a highly-conical egg to avoid rolling off.  Interestingly, a bird that lays a spherical egg often builds a deep nest to inhibit the egg from rolling out.  Shells vary:  a duck egg is oily and waterproof; a group nester differentiates its egg by markings; a cavity nester does not need camouflage and usually produces a white egg; color or spotting provides camouflage, and spotting supposedly strengthens a thin, calcium-deficient shell.  Most captivating is the glossy, iridescent, colorful great tinamou egg (Central and South America).  The reflective shell might even protect the embryo from radiation.  One such egg (different species) was found in Darwin’s belongings.  And as for the smallest and the biggest bird egg…the bee hummingbird egg weighs about 0.2 ounces, and the ostrich egg exceeds 3 pounds.

 

Sandhill Crane with egg - photo Charlie Corbeil

Pesticides endanger an egg.  For example, the bald eagle, our national symbol, ingested fish contaminated with DDT which thinned the eggshell and depleted the population.  In her 1961 book, Silent Spring, Rachel Carson exposed this hazard.  Fortunately, the eagle rebounded.

How does a bird embryo survive?  It feeds on the yolk, and pores in the shell allow it to breathe.  Incubation is vital—sitting on the egg to maintain temperature and periodic turning of the egg for crucial development.  To emerge, the chick pecks out of the hard shell with its egg tooth—pipping.  Always a wonder to behold!

Yet, a bird egg might not produce a hatchling.  For instance, an unfertilized chicken egg is generally used for human consumption.  Also, a single pet female parakeet may lay and needlessly brood a clutch of unfertilized eggs (wind eggs). 

Besides birds, other intriguing creatures lay eggs.  The loggerhead turtle, familiar in Brevard County beaches, lays over 100 eggs at a time.  The queen honey bee may lay 1600 eggs daily during active seasons.  Recently, a Burmese python captured in the Florida Everglades carried 87 eggs.  Remarkably, a tenacious octopus spent 4.5 years brooding an estimated 160 eggs!