Plesiosaur Ecology

by Fortuan

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Plesiosaur Ecology

I t was never the sharks or the pirates that scared me in my seafaring career. It was the disappearance. One day one of my boys was just leaning on the rail looking at the water, and then he was gone. - Ex-Captain of a pirate hunting vessel.

Introduction

Plesiosaurs are marine reptiles that have no discrimination on food. They are very dangerous when hungry and sometimes due to their size they'll always be hungry. They are powerful swimmers and surprisingly quiet ones. They are extremely dangerous to humanoids unfamiliar with the sea and are the cause of many sea voyages returning with a fewer crew.

Physiological Observations

How to Identify a Plesiosaur

Plesiosaurs are a varied group of animals. They share many of the same traits aside from their heads and necks; all Plesiosaurs have 4 flippers and a tail. The tail is usually small and seemingly vestigial, apart from the wide jaw variety who use their massive tails for propulsion. Coated in smooth and sleek scales giving them the sleekness needed for speed in the water, make them agile swimmers. Most varieties have a long neck that ends in a tooth filled head that is very dangerous to any creature small enough. Without their flippers, their bodies resemble large long teardrops. The front of the torso is where most of the organs are contained, which is much larger hindquarters.

Paddle Flippers

The flippers are very close to a paddle from a boat. They swim but "rowing" through the water, with each paddle independent from the other. This movement is swift and fluid, making them very quiet swimmers. This stealth makes them extremely useful hunters as they can surprise a school of fish, and if caught, they can outswim and maneuver any of them. Turning is quick and sharp, with every paddle independently moving.

Origins on Land

A clue that they were once land dwellers is that they are air breathers. Observations records show plesiosaurs holding their breath up to an hour at a time. Breathing seems to be controlled exclusively through the nose holes facing upwards just in-front of the eyes. They seem to stay near the surface of the coastal regions they inhabit with their heads up in the air scanning for prey. When they find a victim, they quietly slip under and dive, out of sight of the fish and then strike from below. They will then chase after the remaining fish, eating until they're full.

Beach Naps

After most of the day in the water, Plesiosaurs return to the beaches to sleep. They crawl up onto dry sand with flippers and lay their heads down, falling asleep. They are dangerous to many animals in the area, so many do not bother to go near them. If awoken before they intend, they instinctually lunge at the source of the disturbance. This reflex seems to be why they seem to sleep out of reach of each other. There are a few observed incidents of accidental attacking, but rarely are the wounds severe or result in retaliation.

Diet and Feeding

While primarily fish eaters, Plesiosaurs will grab anything they can. They snatch birds from the sky and crew off of ships. Their ability to be quiet makes them very hard to notice when they are close. Observers who have seen crew members taken from boats report a snake-like head emerging from the water with no sound. The Plesiosaur will peak its head over the railing, looking for food. They are not aggressive about it but snatch anyone close enough. They prefer to eat things whole, so gnomes and halflings favor more massive humanoids, but they will grab something up to 10 feet tall. If they meet resistance as in attackers striking them, they'll leave for a time. They then will check back after some time and prioritize individuals they deemed as threats and throw them from the ship.

If the prey is too large to swallow, they will grab a victim and swim a few feet below the surface. Usually also correct when catching larger birds or pteranodons. They bite with their needle-like teeth grasping prey and attempting to rip the prey apart. They bite off chunks eating them whole as they go. It seems that they are not able to chew.

Reluctant Fighters with the Right Tools

They are not particularly fond of confrontations or fights, but they do have means to fight. Typically this is seen when on land as they are too slow to run and risk injury simply. They lunge like a snake with their heads almost opening to 150-degree angles. They will bite and grasp enemies attempting to trip or throw them. Most humanoids are unfortunate enough to get tossed into the water, where the Plesiosaur has the advantage. They will then slide off into the water to end the fight with their superior water maneuverability.

Social Observations

Life in the Pod

Plesiosaurs live in pods of 4 to 10 members. They all hunt independently but close by. They dis-coordinated when attacking prey or ships. They will follow the first member to notice in hopes also to find food. This lack of cohesion is not to be said; they don't interact. They will stick close together, and when larger prey is involved, they do take bites and leave for other members to take their turn. Even if the victim perishes, they will still just take a single bit and leave. This practice seems to allow the whole pod to feed without fighting over food.

Acting as Group

They are not patient hunters, so the first pod member to notice a meal usually immediately leaves for the target. The others will then follow but keep a distance of at least 10 feet from each other so as not to cause collisions. When fighting underwater or as a group, this behavior also follows. They seem to be a group of individuals biting from various angles. This tactic is very deadly to most aggressors, although without any coordination, smarter foes usually know to dispatch of Plesiosaur one by one.

Reproduction

In a pod, there is a mix of males and females. Mating occurs frequently and often between feedings. There is no preference for partners. It seems that they are not very fertile and only produce young once or twice every 5 years despite mating all year. Even when a female has a calf mating is accepted and occurs very often.

Gestation

Pregnancy seems not to burden a female in any way. She will not accept mating at this time and will simply swim away from male advances. They seem to round out their shape a bit more towards the end of their body. At later stages of pregnancy, the teardrop shape becomes more and more oval-shaped with a tail. Luckily pregnancy doesn't last and is only a matter of 5 or so months.

Life Cycle

Females give live birth underwater, usually mid-day. The young, just like their parents, are predators and, while disoriented, quickly learn the ropes of swimming. They keep close to the mother until adults. They simply just follow the mother and either eat scraps or learn to fish along-side her. Once fully grown, they stay part of the pod but act independently.

Plesiosaurs seem to live around 20 to 30 years. Prey may be abundant of one kind or another, but since they are not picky eaters as long as there is anything edible, it will stay in an area. Pods will move in roaming for more food on the water and can swim over time great distances. This long-distance travel can cause pods to intersect sometimes. Pods will then just merge as they seem to favor safety in numbers.

Larger Pod Dynamics

Larger pods occur, but not often. They act no differently, but since food diminishes at a higher rate, availability becomes more of an issue. Larger groups run the risk of members starving. Pod members still act individually, and if starving members continue to miss food opportunities, they do eventually die. Larger pods usually don't stay large for many years as members start to die off.

Intra-Species Observations

Prey

Smaller animals, including humanoids, are prey to Plesiosaur. They seem to recognize ships as sources of prey and know to look on deck for easy to grab members. Observers will see a pod of Plesiosaur in the distance with necks out of the water one second and then nothing else. Experienced captains and sailors know to either go below the deck or get your weapons ready. Of course, that's when the crew is lucky enough to spot them first.

In some areas more often traveled, Plesiosaur will start to become more of an issue. Sailors will sometimes mark locations on maps indicating plesiosaurs there. Sometimes stories are exaggerated coming up with great serpents that crash ships. Sometimes as described below, this is not far off.

Sharks

Typically if a fight or larger prey becomes wounded, a lot of blood will permeate the water. This blood brings on their most hated enemies, sharks. They are familiar with sharks and compete with them for food often. Most Plesiosaur will attack sharks on-site, even if the sharks outmatch the Plesiosaurs. This focused aggression has led to humanoid survivors of plesiosaur attacks describing violent battles between hated enemies that allowed them to escape a previously hopeless situation. More giant sharks like megalodon, who are simply massive, are even attacked.

When sharks are spotted, plesiosaurs forgo stealth for aggression. Smaller sharks are wholly overmatched for an enraged pod and are torn to shreds quickly. Fights with megalodon and great whites take longer, but most of the time, the group is victorious as the sharks not usually prey to most anything and don't react quickly enough. Excluding Whale sharks as they are considered whales to a Plesiosaur.

##Variant Species

Long Necks

These are the most common and mostly described above. Long Necks are typically 30 to 40 feet long, with a third to half of that length being their neck. This length allows them to superior reach with their weapons or teeth as we call them. They favor warm coastal regions and are usually teal, blue, or green.

Wide Jaws

These are terrifying variants that are, thankfully, usually solitary. They grow up to 80 feet long with wide crocodilian like heads full of sharp teeth. Some called mosasaurs; they are quite similar to behavior as their long neck cousins aside from usually being solitaire. Mating occurs in every male and female meeting, but they continue on their ways afterward. These have been the cause of capsizing ships as they favor larger prey like whales and mistake ships for whales. They also are entirely water-dwelling as beaching is a much more fatal endeavor to them. They will sleep floating on the surface using individual air sacs. They also hold their breath for up to 3 hours. Their tails are large and paddled to help propel them in the water, unlike other Plesiosaurs. They are more often in open seas away from coasts and in warmer climates. These are generally light blue with white bottoms.

Polar Plesiosaurs

These are very similar to long necks but always have dark black skin to absorb as much heat as possible. They have a specialized chemical that superheats a water jet they can spray at prey and attackers. They usually use this to drill breathing holes in the ice. They still beach themselves to sleep and do not have the snapping instinct. They huddle together for warmth. They are still wet, so a thin coat of ice covers them, but they can breathe by the warm air coming from their nostrils close to the superheated spray vent on top of their head. This superheated chemical is close to that of a polar worm or remorhaz. They are less familiar with ships as the climate usually doesn't allow for ships and avoid them if around.

DM's Toolbox

Plesiosaurs are something fun for water or coastal adventure to mix up a campaign. Dinosaurs usually are a setting on their own, but it's possible to integrate them into any campaign. Here's a few sample encounters below to jog your imagination:

  • Long sea voyage, a lookout on the crow's nest spots weird poles in the distance that disappear. Then suddenly, the cabin boy goes moments later.

  • Deadly encounter in the water with a wide jaw who's mistakenly capsized your ship

  • A fun tiptoe through the beach and a pod of sleeping long necks

  • Polar adventure with a weird frozen breathing mass of black creatures.

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