The Giant Mudpuppy is a "Boulderlizard." Boulderlizards are generally described as hefty, barrel-bodied reptiles that spend most of their day underwater. While both are vastly different, boulderlizards are comparable to shell-less turtles. This connection is often made because, like turtles, boulderlizard species are slow, bulky, egg-laying animals with protected backs and bellies. This kind of organism, however, depends on its weight instead of armor to ultimately survive.

First facing only a few environmental threats, Giant Mudpuppies once lived in relative peace. They quietly fed on the lake’s floor, their teeth slowly changing to perfectly match their preferred diet. Too tough to easily injure and consume, and too heavy to easily maneuver, most hunters were too weak, small, or unintelligent to cause them problems. Yet, the introduction of waterhorses, lakeosaurs, and slitherswims ended this period of safety and peace. Falling to these quick, often serpentine beasts, the boulderlizards evolved to evade their long reach and nocturnal predation. A sizable species, the Giant Mudpuppy evolved a water-retaining organ that can relax or constrict; it also procured a bonier spine, protecting them from the lake’s many large biters. Giant Mudpuppies are the only known member of its kind in Ohio, though others likely exist elsewhere in North America. They utilize their water bladder, heavy, defensive skeleton, and camouflage to endure.

LOCATIONS DISCOVERED   Lake Erie

While the Giant Mudpuppy could theoretically survive in any deep, freshwater lake with a bountiful benthic zone, they are only found in Lake Erie and on its shores. These creatures are also stenohaline and will find solace on land if their environment becomes too salty.

Though this cryptid’s population is densest in the south, individuals frequent the eastern portion of the lake and may be found anywhere within the water’s boundaries. Bottom feeders, Giant Mudpuppies are almost always on the lake floor, hidden under sediment or feeding.

Though its name may suggest that it is a variety of mudpuppy, Giant Mudpuppies are not salamanders at all, but a semi-aquatic reptile species named for their dog-like heads and slick, spotted bodies. Swift, yet inflexible swimmers, they have four short, slender limbs, a stout, pointed tail, and a rotund, yet flattened skeleton covered in thick, smooth skin. The animals range in color from light gray to dark gray and may be densely or lightly speckled on the back with a darker tone.

Rigid and long, these reptiles’ torsos are topped by a prominent spine that arches upwards, peaking just above the hind legs before tapering dramatically downwards. From below, their shadow can resemble an enormous turtle’s; their webbed arms and feet, though, break this illusion. Tied to their access to food, age, and habitat’s size, these animals may grow as large as their environment permits; the largest recorded individual was 25 ft long (from snout tip to tail end), though, in modern times, the maximum size reached is much smaller — 6 - 7 ft long.

When surfacing, these creatures can be misidentified as a porpoise; this is mostly due to their similarly shaped heads. Both have round, short faces with only slight indications of a beak. However, teeth jut from Giant Mudpuppy’s snout and their mouths stretch almost to their necks, making the two immediately distinguishable. These boulderlizards also have several other differing features. Their eyes are oblong and protruding, sitting almost outside of the head completely. A few inches away, wide nostrils flare, taking in oxygen. Below, the animal has a noticeably large overbite with a slight lower jaw. Inside, lining the palate and jaw are several rounded, flat teeth that resemble medicinal tablets. Its neck is incredibly short, the bulky head incapable of much flexibility; like a strange puzzle, its rectangular head connects to a blocky, almost oversized torso, which ends in a stumpy tail that is flattened laterally, like a door stopper set on its side.

When threatened, the Giant Mudpuppy will surface and pose; the way it holds itself somewhat resembles a breaching plesiosaur. This is a method of camouflage used to protect itself from possible predators. For this display, the creature’s body is completely flat and sprawled, but its form only partially comes into view. The animal arches its head upwards and hides its neck and upper back. The arch of its bony spine is visible but also fades back into the water. Irregularly, the creature will raise its tail up and down, giving it more of a serpentine appearance; but, as it is short, this portion of the performance is often overlooked.

Most trips to the surface are not handled this way. When sunbathing, the boulderlizard will expose much of its arched back to warm itself, usually as soon as the sun has risen. Their boney formations in this position resemble a piece of rough wood. When coming up to breathe, the animal will only reach its snout out of the water; it will fill its lungs before descending once more. Surfacing for air is easily missed, as its snout is so thin.

The Giant Mudpuppy is a durophagous bottom feeder. Its diet is predominantly composed of mollusks, mussels, and turtles, though they may consume other macroinvertebrates — such as amphipods, worms, and insect larvae — in addition to small-sized, sickly or injured bottom feeders. With their short necks, heavy heads, and slow bodies, they are unable to catch most kinds of prey.

This animal’s outward-facing, chisel-like teeth are used to pluck shelled prey from the benthic zone; they are uniquely specialized in removing prey from rocks or other hard surfaces. These meals are then moved to the back of the mouth and crushed. The shell is spit out, while the rest is swallowed. Their protruding incisors may also be used to pin and pierce more active prey; in this feeding, the prey is held until lifeless, then consumed. Teeth located on the roof of the mouth assist in grinding and trapping prey.

Giant Mudpuppies rarely feed while on the surface or shore. As they are slower and clumsier, others easily evade them. While they may opportunistically feed on ailing animals, they will not scavenge the dead.

A semi-aquatic, cold-blooded reptile, Giant Mudpuppies only climb to shore for breeding and brumation, the surface to breathe or sunbathe, or either to escape predation. These animals are diurnal, and will spend most of their day feeding, warming, and traveling between favored locations. While they are most active immediately after sunrise, they graze on the lake bed, but move little otherwise for the rest of the day. They do not communicate with one another or vocalize their own needs, wants, or states of mine.

During sunset, the boulderlizards begin burrowing into the benthic layer to rest. They cover themselves in a thin layer of sediment, leaving their back and nostrils exposed. Some choose to hide among the rocks, whereas others choose locations with more organic debris. Sometimes these creatures are pushed out of their hiding places by prodding hunters. Aside from this, some must surface to refill their lungs, descending quickly after to hide until sunrise. Although they can hold their breath for 7 hours while resting, when they are active, they must surface every 2 hours. If stressed, their oxygen reserves are depleted even faster.

Giant Mudpuppies are slow-moving for the most part; they are inefficient swimmers and especially slow and clumsy on land. Because of this, they are prone to predation from larger carnivores. This may be why they have only survived in one region. With their water bladder [See “Anatomy” Figure A] the only means of escape and quick maneuvering, the animals often use land to avoid danger. While many large predators can beach themselves to hunt or utilize a long neck, these boulderlizards usually know how far away is safe and can get there in time. If pressured, they may also rely on camouflage, finding rocks on land and remaining still — hoping their adversary’s senses are poor.

Using their arms and webbed digits to propel themselves forward or change direction, these creatures can swim slowly in a maneuver similar to the ‘breaststroke’ or hover in place to feed. The tail offers a second means of propulsion and is responsible for their greatest speeds [See “Anatomy” Figure F]. While on land, their limbs jut out and their body scrapes against the ground like crocodilians. On land, they cannot move or change direction quickly.

When ice begins to form on the lake’s surface, these placodonts begin brumation. During this process, the animals do not sleep as mammals do during hibernation, but enter a state of dormancy. At this time, their bodies temporarily shut down to conserve energy; they will not move, defecate, eat, drink, or respond to external stimuli as often while in brumation. However, this does not mean that the Giant Mudpuppy will not get up until the spring — in fact, it will wake throughout the season to drink water.

To prepare for brumation, the creatures come to shore and bury themselves along the coast and out of the water’s reach. Giant Mudpuppies congregate in three locations along Lake Erie’s shore for brumation and reproduction; these sites will not be revealed for the animals’ protection.

Giant Mudpuppies reproduce between the ages of 17 and 31. The sexes do not court each other, nor are males and females differentiable without close examination. Oviparous, the animals lay their young on land, fertilize externally, and procreate in large numbers with hopes that some offspring survive into adulthood. Though they do not leave the shore, they lay on its edge; this is the furthest from water the animals will ever go.

In the spring, females dig a shallow hole protected by brush and near where they underwent brumation; there, they lay 3 - 5 unfertilized, round, leathery, gray eggs the size of a marble. Next year, she will winter in one of the two other locations. Male Giant Mudpuppies travel to each of the three nesting grounds after waking from dormancy; they walk the shoreline and fertilize each nest they encounter, covering them with a layer of sediment and debris afterward.

Emerging from the sand in the summer, these freshly hatched boulderlizards stick to the shores and shallows. Extraordinarily small, they exist on an omnivorous diet of zooplankton and phytoplankton until they grow in size and develop anterior teeth. Older hatchlings will feed on larger organic material found in and out of the water, sometimes dragging chunks with them under the sediment. As their lungs are small and weak, they cannot spend very long underwater, finding most of their food on the shore or water’s surface.

Defenseless, once they have eaten and drank, they burrow back into the sand, only emerging to fulfill their needs once more. The hatchlings may become active at any time of day, attracting the attention of both diurnal and nocturnal hunters. These small creatures are often the prey of birds; yet, many predators may pluck them from their hiding places in the sand, or from the surface of the water. Most offspring do not make it to adolescence.

By five years of age, the Giant Mudpuppy is the size of a frisbee. By this time, it has fully developed, but not matured. As ‘plucking teeth’ emerge, they begin attempting to pull mussels from the lake floor and extract the meat from within; with small teeth, they are mostly unsuccessful and clumsy. By the time anterior teeth are fully exposed, they feed with ease and practiced skill. Now adolescents, the animals will swim farther and deeper into the lake and will transition to a purely carnivorous diet. After brumation, they will follow an adult male to other nesting sites. Adolescents may stay in one of these areas for a prolonged time, or venture across the waters, as other placodonts do. Youths are not taught life skills or customs, the knowledge is innately born into them — aside from meeting places, which are symbiotically learned.

Around the age of 16 - 19, Giant Mudpuppies become sexually mature and begin participating in yearly breeding cycles. While the animals may live well into their 30s, their reproductive systems cease to function in their late 20s to early 30s.

This creature is a mostly aquatic organism capable of crude terrestrial navigation. It has two distinct phases of life: one that is omnivorous and mostly inactive, and another that is more active and carnivorous. These stages of life are distinguishable by the animal’s size and the appearance — or lack of — anterior teeth. The species as a whole has a limited range of motion, stocky build, and has a specialized form for benthic zone life.

Figure A  Protective Spine     

The vertebral column is prominent, bony, and its curve looks like a stretched, squashed, and bumpy dorsal fin. Most of these skeletal formations are hidden by sediment while resting; the tallest of these vertebrae resemble rocks following a ridge on the lake bed. These bony knobs may also make the animal more difficult to be eaten by predators (especially when combined with their armored belly), allowing them to escape or survive an attack.

Figure B  Trunk     

Rigid, the trunk is formed by robust ribs that create an armored belly and back, but greatly limit the body’s flexibility. A hardened stomach also protects the creature’s internal organs from harm while navigating on land and the lake bed.

Figure C  Limbs   

Though crude in structure like early land-dwelling creatures, limbs are muscular and capable of carrying the body’s immense weight. The limb's size and structure, however, make movement awkward, slow, and inefficient. If the animal is put under great pressure, limbs are at risk of suffering breaks.

Figure D  Teeth      

Within a tall, heavy, narrow skull, Giant Mudpuppies have 6 anterior plucking teeth, 12 posterior crushing teeth (which are rounded, flat, and broad), and 4 palate teeth (which are also round, flat, and broad); these teeth aid in their predation of bivalves and other shelled animals.

Figure E  Water Bladder    

Generally, boulderlizards are negatively buoyant and have no difficulty remaining on the lake bed to feed. Unlike others of their order, however, Giant Mudpuppies have developed an organ to allow them to move quickly vertically. Connected to the esophagus, the water bladder takes in large quantities of water when in use, and propels it outside of the body through the cloaca. Surrounded by bands of strong muscles, the body constricts along with these specialized fibers; with this motion, the water bladder is compressed with great strength. Once empty, water is taken in through the esophagus and cloaca. The process is repeated and with speed, force. While excreting, the esophagus is tightened shut, and pathways to the lungs are blocked — oxygen reserves are quickly depleted; however, some oxygen is still taken into the body, absorbed through the lining of the cloaca. After use, the animal is disoriented and must surface to fill their oxygen reserves.

The Giant Mudpuppy utilizes its water bladder to its full potential to escape danger. In this process, the water above and below the animal churns violently, sometimes disrupting the swim of other creatures or alerting surface dwellers of the beast’s imminent presence. When on the surface, the animal will turn belly up, fill with water to sink slightly, then pump its water bladder to quickly shoot downwards. Water bladder use is gentler and less noticeable in non-threatening situations.

Figure F  Tail     

A sideways flattened, short tail helps Giant Mudpuppies steer and paddle while in water.

Figure G  Parietal Eye     

A light-sensitive organ, the parietal eye regulates behavior associated with the time of day and allows the animal to orient itself correctly when seeking the water’s surface.

Figure H  Cloaca     

Unlike other animals with a cloaca, this opening is found higher up on the torso, almost in the midsection. It is likely that the cloaca’s position evolved in tandem with the success of its water bladder. The cloaca is not only important for excretion or its role in water navigation but respiration. When resting underwater, the animal takes oxygen in and diffuses carbon dioxide out through the cloacal opening; this process is sustained by a flow of water running over the animal and is paired with the pumping of the water bladder. When the water bladder is in use, cloacal respiration provides the animal with enough oxygen to function; in stressful situations, cloacal breathing can only sustain the creature a short time, as its oxygen needs are too great.