Pinnipeds—Blurring the Boundaries

It’s a bird, it’s a fish, it’s a beast of the land—as we look around, we love to categorize creatures into neat little niches. But what about those strange creatures that dip their fins in two different worlds? What lessons does this blurring of the lines teach about God’s creation?

Our mindset vastly influences how we view the world. Whether we’re looking at newly discovered fossils that are paraded before the public as transitional forms or we’re observing living creatures that share similar traits with other kinds of creatures, we depend on our worldview to connect the dots and deduce family relationships among creatures.

Whether it’s platypuses, pronghorns, or pinnipeds, several animals have a combination of traits other creatures possess. But we don’t have to assume these similarities prove anything about their ancestry. It’s just as reasonable to conclude their mixture of traits came from the lavish design of the Creator as to say it came from evolution.

Some of us, myself included, get in our heads that everything in nature must be cut and dried, black or white, this or that. But God didn’t promise us a simple world that’s easy to pigeonhole. He did say that He created all life “according to their kinds,” but He didn’t mention the number of kinds or promise that the differences between the kinds would always be obvious.

The deeper we dig into a subject, the more we usually find things that are hard to categorize.

Scientists like me are tidy-minded. We like to systematize, categorize, and name everything we study, whether it’s in biology, ecology, theology, or chemistry. But the deeper we dig into a subject, the more we usually find things that are hard to categorize.

Consider ecology. Ecologists study many discreet habitats, such as lakes, rivers, mountains, woodlands, and prairies. But habitats don’t abruptly change from one to another. Boundaries blend; they’re rarely sharp. Where different habitats meet, the annual rainfall, temperature, and humidity can be unique, supporting specialized plant and animal communities that are often intermediate between the neighboring habitats.

So when some critter (alive or extinct) appears to represent a transition between different kinds of animals and seems to fit nicely into an evolutionary story, there’s no need to worry. Surely, if we believe everything the Creator said in His infallible Word, we should expect to find a powerful alternative interpretation. We should share Job’s confidence: “Ask the beasts, and they will teach you . . . that the hand of the Lord has done this” (see Job 12:7–9).

Consider the Pinnipeds

Many creatures share similar body traits with other, vastly different creatures. Let’s say the body shape, or morphology, of creature B is somewhere between creature A and creature C. Does this mean that creature B is “transitional,” in the sense that it is evolving from something like A into something like C, or could it have been designed to inhabit transitional spaces between the habitats of creatures A and C?

Consider the pinnipeds, which I mentioned above. You probably know them by their more common names—walruses, seals, and sea lions. They serve as a great example of how evolutionists and creationists come up with totally different conclusions based on their radically different worldviews. Seals and walruses have a combination of traits that allows them to straddle two very different worlds: land and water. But does that mean they are in some sort of evolutionary transition? Not at all!

Evolutionists believe they must have descended from a more terrestrial bear- or weasel-like mammal (creature A) about 23 million years ago and gradually evolved into the sea but still have ties to land (creature B). Evolutionists would probably say that they could become completely aquatic in several more million years if they continue to evolve in that direction (creature C).

But we should not view them as “creatures in transition.” We should take them at face value: wonderful, playful, intelligent creatures specially designed to thrive in semiaquatic environments. Amazingly, they are able to sleep, molt, mate, and give birth on land, ice, or water.

Is God trying to confuse us? Of course not! It’s easy to see why these creatures do things the way they do. These delightful mammals are uniquely equipped to inhabit an intermediate space that might otherwise be sparse of life’s rich variety. They give magnificent testimony to the Creator, who filled His world with wonders reflecting His wisdom and glory (Romans 1:20).

Designed for Land and Sea

Pinniped means “fin-footed animals.” Their foot bones form flippers instead of feet. These flippers give them a huge advantage in propelling their bodies through the water. (No wonder scuba divers don flippers!)

The three pinniped families display some interesting variations in body design: the eared seals (Otariidae), the true seals (Phocidae), and the walruses (Odobenidae).

The eared seals, which include the sea lions and fur seals, have external ear flaps. On land they are capable of walking on all fours because their front and rear flippers can bear weight, rotate, and push the body along in an awkward-looking motion. In the water they are quintessential swimmers and move with awe-inspiring grace and speed. They flap their front flippers to “fly” through the water like penguins, using their hind flippers as a rudder.

The true seals don’t have visible external ear flaps, and they are even more streamlined for underwater swimming. Their front and back flippers play the opposite roles of eared seals’ flippers. Their hind flippers move side to side to propel them through the water, like a fish, while the front flippers steer. On land neither set of flippers can rotate and they are virtually useless for getting around. Instead they undulate their bodies caterpillar-like to scoot around.

The third pinniped family has only one member, the walrus. They are most well-known for their long tusks, pronounced whiskers, and sparse fur. The lack of fur makes them appear essentially bald. The whiskers are plentiful, movable, and packed with a good blood supply and sensory nerves. Though their whiskers may give them the distinguished look of an obese monarch, they serve as very sensitive underwater feelers to help walruses find food in the dark and murky depths.

Some of the walrus morphology (body shape) and swimming behavior is shared with eared seals and some is shared with true seals. Specifically their flippers rotate so they can move about on land more in the fashion of eared seals. But in the water, they use their rear flippers in much the same way as true seals do. Walrus flippers also have thick, rough soles to give them extra traction when they are scooting around on a slick sheet of floating ice.

Underwater Vision

When we swim underwater, everything looks terribly out of focus, but pinniped eyes were divinely designed to see above and under water. The details are complex, but basically their lens is more spherical than ours, which are relatively flat, enabling them to focus the light more effectively underwater. They also have an extra blinkable eyelid made out of a clear membrane that protects their eyes while submerged.

Wetsuits for Warmth

Seals (but not walruses) have a dense layer of fur. Both seals and walruses also have a layer of blubber beneath their skin. Fur and blubber provide excellent insulation from the chilly air and water they inhabit. (Fur seals actually have two kinds of fur: water-repelling guard hairs and dense underfur for insulation.)

Streamlined for Speed

The blubber also provides stored energy, buoyancy, and a more streamlined shape. Seals’ and walruses’ mammary glands, which provide milk for the young, do not protrude but are tucked away under slits in their skin to maintain their streamlined shape.

Designed to Dive

Pinnipeds can hold their breath up to 80 minutes (max) while foraging for food. God specially designed their bodies to hold their breath so long. When they dive, their heart rate decreases. Certain arteries open up to shunt blood to where it’s needed most while others constrict, shutting off blood to the skin and extremities.

Pinnipeds’ metabolism drops greatly so their oxygen supply is used sparingly. And it’s an ample supply. Compared to humans they have twice as much blood pound for pound. They also have a special design that allows them to store extra oxygen in their muscle tissue, not just in their red blood cells.

Their lungs are designed to handle high water pressure during deep dives. The lungs will collapse and then reinflate when they surface. This is very useful because large, inflated lungs would be quite buoyant, making deep dives difficult.

Batten Down the Hatches

Pinnipeds were beautifully designed with a set of muscles that automatically close their nostrils when they take a dive. Not so with us. We must find less elegant ways to prevent the “water up the nose” problem.

Awake While Asleep.

Often pinnipeds have to sleep out at sea. How do they defend themselves against predators like sharks and orcas when they are far from land?

Scientists have discovered that they are able to keep one half of their brain awake while the other half sleeps. The halves can take turns napping so that one side of the brain is always on alert in case a predator is on the prowl. However, when they snooze on land their whole brain can take a nap.

Missing Links?

It appears that God wanted the earth to be filled with a vast assortment of habitats and microhabitats. It should come as no surprise that He made a startling array
of creatures to fill them all.

It’s easy to see how all these special designs point to God’s special creation of every animal kind on Days Five and Six. We can confidently conclude that God equipped these marvelous creatures for their unique way of life: a life that is comfortable both in and out of water. God’s handiwork is so “clearly seen” that we are “without excuse” (Romans 1:20).

Yet since mankind has rejected the truth of God’s Word, people are desperate to find an alternative explanation for all these wondrous creatures, both living and fossil. Is it any surprise how they interpret new findings of animals that seem to share traits from two different living creatures? Back in 2009 the headlines were filled with news of a fossilized “seal with legs,” named Puijila darwini. If you heard the news, how did you respond? How would you respond after reading this article?

We need to understand that God was lavish in His biological creation. It appears that He wanted the earth to be filled with a vast assortment of habitats and microhabitats. It should come as no surprise that He made a startling array of creatures to fill them all.

When we understand that God is the master engineer who forms creatures perfectly suited to in-between habitats, we should realize the misuses of the term “transitional.” Such creatures are not transitional forms that have evolved midway from one form into another. Rather, their wonderfully designed bodies enable them to thrive in a different habitat, possibly intermediate between very different adjacent habitats.

Will evolutionists get mileage out of in-between looking creatures? They will certainly try, based on their worldview, but there’s no need for us to fret and explain away the traits in order to defend our biblical worldview. Understanding that the pinnipeds were created for their unique lifestyle gives us a fresh perspective on species that are now extinct.

We should expect to find variations with different body shapes and abilities that were admirably suited to live in in-between habitats that are difficult for us to reconstruct. The fossil remains of Puijila darwini, for example, were found on a frigid island in northern Canada that’s now uninhabitable. Its skeleton is very otter-like but it has some cranial and dental features similar to seals. Do these features prove that it was an ancestor of the pinnipeds? How should a creationist interpret this find without denying its seal-like characteristics?

Will we put our faith in our own limited, fallible experience with animals and environments around today, or will we trust God’s eternal, infallible Word? Each time a new transitional creature is touted, why not thoughtfully consider the limitless possibilities that only the Creator God could imagine and create!

Seals & Walruses—Across All Boundaries

The Creator custom-designed three families of mammals that are at home on land or sea—earless “true seals,” eared seals, and walruses. Despite centuries of slaughter by humans, these champion swimmers still grace the coasts of every continent and many far-flung islands of the world.

Seals and Walruses

Seals/Walruses described clockwise from left to right.

California Sea Lion: There are six surviving species of sea lions. Many of the trained “seals” that you see in circuses are actually California sea lions.
Walrus: The walrus is easily recognizable by its whiskers and long tusks, which it drags through the seafloor to help stir up food. Its tusks can reach 3 feet (1 m).
Ribbon Seal: At birth the ribbon seal is completely white, and the distinctive ribbon pattern gradually appears in adulthood. This seal lives entirely in the open sea during the summer and fall.
Baikal Seal: Located in Siberia’s Lake Baikal, this is one of only three seal species that live in freshwater. One of the smallest of the true seals, it reaches only 4 feet (1.3 m) in length.
Southern Elephant Seal: The elephant seal is the largest pinniped. In fact, it is one of the largest land animals. Males can reach 19 feet (5.8 m) in length and weigh up to four tons.
South African Fur Seal: This “fur seal” belongs to the same family as sea lions. Notice the visible ears and how the front fins support some of their weight, which allows them to scoot along the shore.
Crabeater Seal: This is the most common seal in the world, with an estimated population up to 75 million. Unlike its name, the seal feeds on shrimplike creatures called krill, abundant in the Antarctic.

3 Families of Pinnipeds

Earless Seals: “True” seals are earless. They look like a blubbery torpedo because their front fins tuck against their sides and are not used for walking.

Eared Seals: The eared seals include sea lions and various “fur seals.” Their front fins fold under their bodies and help them waddle around on the shore.

Walrus: With its unique tusks, the walrus belongs to a separate family. They are earless like earless seals, but they waddle like eared seals.

Dr. Gordon Wilson, Senior Fellow of Natural History at New Saint Andrews College, earned his PhD from George Mason University in Environmental Science and Public Policy. He holds a master of science degree in entomology from the University of Idaho.

Answers Magazine

October – December 2013

With an updated interior design, the fall issue has it all, from breaking down the big bang to building a better understanding of dinosaurs, from public schools to pinnipeds, and from archaeological discoveries at Çatalhöyük to the astronomical delight of a Christmas comet.

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