The Scribblings of Samuel Baughn

Hyaenodonts in GURPS

A very successful and diverse order of predators, Hyaenodonts resembled modern carnivores like wolves and lions, but weren’t closely related to them. They were Creodonts, a now extinct clade of meat-eaters. They were generally more carnivorous than even the carnivore clade, with teeth unsuited for anything except flesh. Most of them were had sturdy builds, short legs, and long heads.

They thrived in the warm climate of the Oligocene, then died off as global temperatures fell and landscapes shifted from dense woodland to open plains during the Miocene.

Apterodon

A small, semi-aquatic genus which used its strong jaws to crack shellfish open. Powerful front limbs allowed it to dig burrows for shelter.

ST 6; DX 12; IQ 3; HT 11.

HP 6; Will 11; Per 11; FP 11; Speed 6.00; Dodge 9; Move 8.

SM −1, 25 lbs.

Bite (14): 1d−2 cutting.

Traits: Amphibious; Bad Sight (Low Resolution); Born Biter 2; Breath Holding 5; Discriminatory Smell; Enhanced Move 1 (Ground Speed 16; Costs Fatigue, 1 FP/second); Night Vision 3; Striking ST 3 (Bite only); Quadruped; Ultrahearing; Wild Animal.

Skills: Brawling-14; Survival (Island/Beach)-13; Swimming-15.

Hyainalouros

A very big animal, possibly the largest hyper-carnivorous mammal ever. Despite its size, it was well suited for running. Megistotherium may be a close relative or even the same genus. Either way, it attained similar sizes, as did Simbakubwa.

ST 21; DX 10; IQ 3; HT 11.

HP 21; Will 12; Per 11; FP 11; Speed 5.00; Dodge 8; Move 5.

SM +2 (3 hexes), 1,100 lbs.

Bite (12): 3d+1 cutting.

Claw (12): 2d+1 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 2; Discriminatory Smell; DR 3; Enhanced Move 2 (Ground Speed 20; Costs Fatigue, 1 FP/second); Night Vision 3; Striking ST 6 (Bite only); Parabolic Hearing 2; Quadruped; Ultrahearing; Wild Animal.

Skills: Brawling-12; Survival (Woodland)-12.

This profile represents a compromise between several wildly different size estimates for these animals. The smallest estimate would instead weigh around 600 lbs. and have ST and HP 17 (damage 2d+2 with a bite, 1d+2 with a claw), SM +1, Born Biter 3, and DR 2. The largest would be 3,300 lbs. and have ST and HP 30 (damage 4d+2 with a bite, 3d+2 with a claw), SM +3, Born Biter 1, and DR 4.

Hyaenodon

These dog-like creatures came in a huge variety of species, ranging from terrier to bear sized. All of them had large heads with long, powerful jaws. They seem to have used a combination of stalking, pouncing, and pursuit to capture prey, like lions. Sturdy teeth suggest they would bite and then hang on to struggling prey, also reminiscent of lions. Dissopsalis was a later genus with similar anatomy which survived into the late Miocene. Pyrocyon was another dog-shaped animal, a little smaller than the smallest Hyaenodon species. It lived in the early Eocene and, like a dog, was able to eat a wider variety of food than most of its relatives.

ST 9; DX 11; IQ 3; HT 11.

HP 9; Will 12; Per 11; FP 11; Speed 6.00; Dodge 9; Move 8.

SM 0, 80-90 lbs.

Bite (13): 1d cutting.

Claw (13): 1d−2 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 3; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 16; Costs Fatigue, 1 FP/second); Night Vision 3; Striking ST 4 (Bite only); Parabolic Hearing 2; Quadruped; Ultrahearing; Wild Animal.

Skills: Brawling-13; Climbing-12; Survival (Woodland)-14.

This profile suits mid-sized species such as H. horridus or H. leptorynchus or Dissopsalis. For a small species such as H. crucians (40 lbs.) reduce ST and HP to 7 and Striking ST to 3 (bite damage 1d−1, claw damage 1d−3). For the smallest, such as H. microdon and H. mustelinus (11 lbs.) or Pyrocyon (6 lbs.), reduce ST and HP to 4 and Striking ST to 2 (bite damage 1d−4, claw damage 1d−5) and remove DR. For the giant species like H. gigas, H. mongoliensis, and H. weilini (800-900 lbs.) raise ST and HP to 19, DR to 2 and Striking ST to 6 (bite damage 2d+3, claw damage 2d).

Kerberos

A large early Hyaenodont from Eocene Europe. It was a jaguar-sized ambush predator, poorly suited to running. It shared its habitat with the far smaller but generally similar Lesmesodon, which resembled a cross between a fox and a weasel. Exceptionally well-preserved remains show that it had long brown fur and a bushy tail. Galecyon was another small animal with a combination of canine and mustelid features from the same place and time, which spent more time on the ground.

ST 13; DX 11; IQ 3; HT 11.

HP 13; Will 11; Per 11; FP 11; Speed 6.00; Dodge 9; Move 6.

SM 0, 300 lbs.

Bite (13): 1d cutting.

Claw (13): 1d−2 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 3; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 12; Costs Fatigue, 1 FP/second); Night Vision 3; Striking ST 5 (Bite only); Parabolic Hearing 2; Quadruped; Temperature Tolerance (Heat) 2; Ultrahearing; Wild Animal.

Skills: Brawling-13; Climbing-12; Survival (Jungle)-12.

For Lesmesodon (1 lb.) reduce ST and HP to 2, SM to −4, Striking ST to 1 (damage 1d−5 with a bite, 1d−6 with a claw), and remove DR. For Galecyon (15 lbs.) reduce ST and HP to 5, SM to −2, Striking ST to 2 (damage 1d−3 with a bite, 1d−4 with a claw), increase Enhanced Move to 1.5 (Ground Speed 18), and remove DR and Climbing skill.

Dimetrodon in GURPS

Dimetrodon and Edaphosaurus (back) by Charles R. Knight (1897)

Dimetrodon is the most famous early synapsid. Indeed it is likely the only one which most people would recognize. Despite appearing alongside dinosaurs in works of fiction and cheap plastic toys, it died out millions of years before they evolved. Although sometimes called ‘mammal-like reptiles’, Dimetrodon and its relatives aren’t actually reptiles either. It did look reptilian, however, with scaly skin, sprawling legs, a thick tail, and a spectacular sail running along its spine.

The sail's purpose remains hotly debated. The leading theory suggests it regulated body temperature, capturing morning sunlight and managing heat throughout the day. Other hypotheses propose it served for sexual display, rival intimidation, or spinal stabilization during rapid movement. The apparently conspicuous sail might have actually provided camouflage by mimicking the silhouettes of plants or harmless herbivores. Rather than the commonly depicted thin membrane, the sail could have been a fleshy hump storing fat and fluids for lean periods. More outlandish theories include it functioning as a sensory organ for detecting wind and air vibrations, or even acting as an actual sail when swimming!

As one of its era's biggest land animals, Dimetrodon was an apex predator. Later species grew even larger with proportionally bigger sails. Though favoring wetland habitats, these adaptable beasts could survive in arid environments as well.

Dimetrodon

ST 16; DX 11; IQ 2; HT 13.

HP 16; Will 12; Per 10; FP 13; Speed 5.00; Dodge 8; Move 4.

SM +2 (4 hexes), 500 lbs.

Bite (13): 1d+1 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 2; Cold-Blooded (50°); Discriminatory Smell; DR 2; Enhanced Move 1 (Ground Speed 8; Costs Fatigue, 1 FP/second); Quadruped; Wild Animal.

Skills: Brawling-14; Survival (Swampland)-14; Swimming-13.

This profile suits the later and larger species such as D. angelensis or D. grandis. Earlier species such as D. natalis (60 lbs.) could have ST and HP as low as 8 (bite damage 1d−3) and DR 1.

Metailurini in GURPS

The ‘dagger-toothed cats’ never got as large as the biggest saber-toothed cats. They had robust, conical, and relatively short fangs, well suited to throttling struggling prey. Their tails were almost as long as those of modern cats.

Dinofelis

This bulky ambush predator had powerful forelegs, which helped both in climbing and subduing prey.

ST 14; DX 13; IQ 4; HT 11.

HP 14; Will 10; Per 12; FP 11; Speed 6.00; Dodge 10; Move 7.

SM 0, 330 lbs.

Bite (15): 1d impaling.

Claw (15): 1d cutting.

Traits: Bad Sight (Low Resolution); Born Biter 1; Combat Reflexes; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 14; Costs Fatigue, 1 FP/second); Limited Camouflage; Night Vision 3; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-14; Climbing-16; Stealth-13; Survival (Woodlands)-13.

Metailurus

This cat’s long, powerful legs allowed it to make impressive leaps, ideal for pouncing from ambush.

ST 10; DX 13; IQ 4; HT 11.

HP 10; Will 10; Per 12; FP 11; Speed 6.00; Dodge 10; Move 12.

SM 0, 110 lbs.

Bite (15): 1d−2 impaling.

Claw (15): 1d−2 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 1; Combat Reflexes; Discriminatory Smell; Limited Camouflage; Night Vision 3; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-14; Climbing-15; Jumping-16; Stealth-14; Survival (Woodlands)-12.

Yoshi

A cheetah-like animal with a slender build, long-legs, and short muzzle.

ST 9; DX 13; IQ 4; HT 11.

HP 9; Will 10; Per 12; FP 11; Speed 6.00; Dodge 10; Move 13.

SM −1, 85 lbs.

Bite (15): 1d−2 impaling.

Claw (15): 1d−2 cutting.

Traits: Born Biter 1; Combat Reflexes; Discriminatory Smell; Enhanced Move 1 (Ground Speed 26; Costs Fatigue, 1 FP/second); Limited Camouflage; Night Vision 1; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-15; Running-16; Stealth-14; Survival (Plains)-12.

Homotherini in GURPS

The ‘scimitar cats’ had lighter builds and were better adapted for running than their relatives the Smilodontini. It is believed that their flattened and serrated fangs would have been fully covered by lips. Their overall appearance would have been similar to modern cats, mostly distinguished by their short tails.

Amphimachairodus

A huge cat, even larger than Smilodon populator, with relatively short legs, necessitating ambush as its main hunting strategy. Sexual dimorphism in size suggests that it was a social animal. It seems to have preferred smaller prey. Its close relative Nimravides was better built for speed and preferred big game. It seems to have used its jaws in a manner similar to modern big cats, clamping onto the throat to strangle large prey. The largest species, N. catocopis, was similar in size to Amphimachairodus, but others were less than one-third their weight.

ST 19; DX 12; IQ 4; HT 12.

HP 19; Will 10; Per 12; FP 12; Speed 6.00; Dodge 10; Move 9.

SM +1 (2 hexes), 900 lbs.

Bite (14): 2d impaling.
Claw (14): 2d cutting.

Traits: Bad Sight (Low Resolution); Born Biter 1; Chummy; Combat Reflexes; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 18; Costs Fatigue, 1 FP/second); Limited Camouflage; Night Vision 3; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-14; Stealth-14; Survival (Plains)-14.

For Nimravides catocopis, increase Move to 10, (Ground Speed 20 with Enhanced Move), and remove Chummy. Smaller species such as N. galiani (260 lbs.) and N. thinobates (300 lbs.) also reduce ST and HP to 13 (bite and claw damage 1d) and SM to 0.

Homotherium

A relatively slender, long-legged cat, well suited to high-speed chases across open ground. Well-preserved remains show that it had a plain brown coat as an infant. It seems to have hunted very large prey, which indicates it probably hunted in groups. Its relative Lokotunjailurus was even more lightly built. Both had enlarged dewclaws to assist in grappling prey.

ST 15; DX 13; IQ 4; HT 11.

HP 15; Will 10; Per 12; FP 11; Speed 6.00; Dodge 10; Move 10.

SM +1 (2 hexes), 440 lbs.

Bite (15): 1d+1 impaling.
Claw (15): 1d+1 cutting.

Traits: Born Biter 1; Chummy; Combat Reflexes; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 20); Night Vision 1; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-15; Running-13; Stealth-12; Survival (Plains)-12; Wrestling-15.

For Lokotunjailurus, reduce ST and HP to 12 (bite and claw damage 1d−1), SM to 0, increase Move to 12 (Ground Speed 24 with Enhanced Move), and remove Chummy.

Xenosmilus

The ‘cookie-cutter cat’ not only had two large slicing fangs, but also serrated incisors. It is believed to have used these to carve chunks out of its victims, killing them slowly from blood loss. It was a bulky animal, almost bear-like in its proportions.

ST 18; DX 11; IQ 4; HT 12.

HP 18; Will 10; Per 12; FP 12; Speed 6.00; Dodge 10; Move 8.

SM +1 (2 hexes), 770 lbs.

Bite or Claw (13): 2d cutting.

Traits: Bad Sight (Low Resolution); Born Biter 1; Combat Reflexes; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 16; Costs Fatigue, 1 FP/second); Limited Camouflage; Night Vision 3; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-13; Climbing-13; Stealth-14; Survival (Woodlands)-12.

Smilodontini in GURPS

Promegantereon was the earliest known member of the ‘dirk-toothed cats’. It was leopard-sized and well suited to climbing. Although it had long upper canines and reduced incisors, these features weren’t nearly as pronounced as they would become in later genera. Its descendant Paramachaerodus had somewhat more powerful shoulders, indicating a preference for grappling with claws before using its teeth. Rhizosmilodon was a larger and more robust animal, but still lacked truly massive fangs. Megantereon was even bigger and did have long fangs, but was still smaller and less well armed than Smilodon fatalis. It also had a distinctive flange under its chin, a feature which convergently evolved in many other saber-toothed predators.

Promegantereon

ST 10; DX 13; IQ 4; HT 11.

HP 10; Will 10; Per 12; FP 11; Speed 6.00; Dodge 10; Move 10.

SM 0, 140 lbs.

Bite or Claw (15): 1d−2 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 2; Catfall; Combat Reflexes; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 20; Costs Fatigue, 1 FP/second); Flexibility; Limited Camouflage; Night Vision 3; Parabolic Hearing 1; Quadruped; Silence 1; Ultrahearing; Vibration Sense (Air; Short Range 1); Wild Animal.

Skills: Brawling-15; Climbing-16; Stealth-14; Survival (Woodlands)-12.

For Paramachaerodus, add Wrestling-14.

Rhizosmilodon

ST 11; DX 12; IQ 4; HT 12.

HP 11; Will 10; Per 12; FP 12; Speed 6.00; Dodge 10; Move 10.

SM 0, 170 lbs.

Bite or Claw (14): 1d−1 cutting.

Skills: Brawling-14; Climbing-14; Stealth-14; Survival (Woodlands)-12; Wrestling-14.

Techniques: Targeted Attack (Brawling Bite/Neck)-12.

Megantereon

ST 12; DX 12; IQ 4; HT 12.

HP 12; Will 10; Per 12; FP 12; Speed 6.00; Dodge 10; Move 10.

SM 0, 220 lbs.

Bite (14): 1d−1 impaling.

Claw (14): 1d−1 cutting.

Skills: Brawling-14; Stealth-14; Survival (Woodlands)-12; Wrestling-14.

Techniques: Targeted Attack (Brawling Bite/Neck)-12.

Ground Sloths in GURPS

Ground sloths are an example of a body-plan which has evolved several times in mammals; large semi-upright herbivores with formidable claws on their forelimbs. They were ancestral to modern sloths, but were very different in appearance and habits.

They usually walked on all fours, resting their weight on the knuckles of their ‘hands’ and the outer edges of their back feet. These feet were very strange, with the inner toes being rotated away from the ground so that their claws turned inwards. At the back of each foot was a bony extension, resembling an additional toe. Despite this curious anatomy and the great size of some of the sloths, it seems they were able to rear up on their hind limbs, using their thick tails as a third point of support. This allowed them to reach up into tall trees to bring buds, leaves, and fruit close enough to seize with their prehensile lips. It seems likely that they also used their claws for defense and competition with each other for mates.

Their metabolisms appear to have been fairly slow, a feature they share with modern sloths. Combined with their bulk and thick coats of fur offering significant insulation, they would have been able to survive on a relatively meager diet.

Megalonychids

Megalonyx (‘Great Claw’) remains were first discovered in West Virginia and named by Thomas Jefferson, who published a paper on them. Jefferson assumed that the claws must have come from a giant predator, only later learning of the existence of Megatherium and concluding that the two creatures must be related. It was a fairly typical ground sloth, distinguished mostly by the fact it lived in the pine woods of North America. Its ancestor Pliometanastes was only slightly smaller and crossed into North America before it had fully joined to South America by island-hopping. Their South-American relative, Ahytherium was only about two-thirds their weight.

Megalonyx

ST 25; DX 9; IQ 2; HT 12.

HP 25; Will 10; Per 10; FP 12; Speed 4.00; Dodge 7; Move 4.

SM +2 (3 hexes), 2,000 lbs.

Claw (11): 2d+3 cutting.

Traits: Bad Sight (Low Resolution); Discriminatory Smell; DR 3; Night Vision 1; Reduced Consumption 2 (Food Only); Semi-Upright; Temperature Tolerance (Cold) 3; Wild Animal.

Skills: Brawling-11; Survival (Woodlands)-10.

Use the same profile for Pliometanastes. For Ahytherium (1,300 lbs.) reduce ST and HP to 22 (claw damage 2d+1).

Megatherids

Megatherium was one of the largest ground sloths, around the size of an Asian elephant. It had an even more robust skeleton and proportionally longer claws that its relatives. Its relative Eremotherium was even larger and lived in warmer regions, so it may have had little or no fur.

Megatherium

ST 41; DX 8; IQ 2; HT 13.

HP 41; Will 10; Per 10; FP 13; Speed 4.00; Dodge 7; Move 5.

SM +3 (10 hexes), 8,500 lbs.

Claw (10): 4d+5 cutting or impaling.

Traits: Bad Sight (Low Resolution); Discriminatory Smell; DR 4; Night Vision 1; Reduced Consumption 2 (Food Only); Semi-Upright; Temperature Tolerance (Cold) 2; Wild Animal.

Skills: Brawling-10; Survival (Woodlands)-10.

For Eremotherium (10,000 lbs.) increase ST and HP to 43 (claw damage 5d+3) and remove Temperature Tolerance.

Mylodontids

Some members of this family had numerous small bony plates embedded in their skin, making them very challenging prey even for fearsome predators such as Smilodon populator. Mylodon lived in the Southern end of South America and was around the size of a modern rhinoceros. Although it mostly ate grasses, there is evidence that it also enjoyed meat from time to time, probably scavenged carrion or the remains of unfortunate predators which misjudged the sloth. Its close relative Paramylodon lived in North America, and was very similar. Lestodon lived slightly further North of Mylodon and grew to the size of an elephant. Glossotherium was smaller, and avoided predators and inclement weather by digging immense burrows. Catonyx was a distant relative which grew to about the same size as Mylodon, while Scelidotherium and Thinobadistes were only about half its weight.

Mylodon

ST 31; DX 9; IQ 2; HT 12.

HP 31; Will 10; Per 10; FP 12; Speed 4.00; Dodge 7; Move 4.

SM +3 (8 hexes), 3,600 lbs.

Claw (11): 3d+6 crushing.

Traits: Bad Sight (Low Resolution); Discriminatory Smell; DR 5; Night Vision 1; Reduced Consumption 2 (Food Only); Semi-Upright; Temperature Tolerance (Cold) 2; Wild Animal.

Skills: Brawling-11; Survival (Plains)-10.

Use the same profile for Paramylodon. For Lestodon (9,000 lbs.) increase ST and HP to 42 (claw damage 4d+9), and DR to 6. For Glossotherium (2,800 lbs.), reduce ST and HP to 28 (claw damage 3d+4), SM to +2, DR to 4. For Catonyx, reduce DR to 3 and Temperature Tolerance to 1. For Scelidotherium (1,900 lbs) or Thinobadistes (2,000 lbs.) reduce ST and HP to 25 (claw damage 2d+5), SM to +1, DR to 2, and Temperature Tolerance to 1.

Nothrotherids

Although not as impressive as the truly giant sloths, these bear-size animals still had thick hide and fearsome claws. Nothrotherium lived in dry, open forests and may have been able to climb trees, while Nothrotheriops was slightly larger and lived in arid scrubland.

Nothrotherium

ST 14; DX 10; IQ 2; HT 12.

HP 14; Will 10; Per 10; FP 12; Speed 4.00; Dodge 7; Move 4.

SM +1 (3 hexes), 330 lbs.

Claw (12): 1d cutting.

Traits: Bad Sight (Low Resolution); Discriminatory Smell; DR 2; Night Vision 1; Reduced Consumption 2; Semi-Upright; Wild Animal.

Skills: Brawling-12; Climbing-12; Survival (Woodlands)-10.

For Nothrotheriops (550 lbs.) increase ST and HP to 16, remove Climbing skill and replace Survival (Woodlands) with Survival (Desert)-13.

Hemicyon in GURPS

Although the ‘dog-bear’ was more closely related to modern bears than dogs, it was extremely dog-like in appearance (although more robust and with a larger head than modern canines of its size). Its diet was highly carnivorous and it was probably a pursuit predator.

Hemicyon

ST 10; DX 12; IQ 4; HT 12.

HP 10; Will 12; Per 12; FP 12; Speed 6.00; Dodge 9; Move 9.

SM 0 (2 hexes), 110-140 lbs.

Bite (14): 1d-3 cutting.

Traits: Bad Sight (Low Resolution); Born Biter 2; Discriminatory Smell; DR 1; Enhanced Move 1 (Ground Speed 18); Night Vision 1; Parabolic Hearing 1; Quadruped; Ultrahearing; Wild Animal.

Skills: Brawling-14; Stealth-12; Survival (Plains)-14.