Limits by Larry Niven (books to read for 13 year olds txt) 📕

got the spare time. We’ve been through this. Pack up the deep-radar and let’s move.”

Now the rolling hills of feather-wheat sloped gently up toward an eroded mountain range whose peaks seemed topped with pink cotton. The three-legged female, Gimpy, trotted alongside Rachel, talking of star travel. Her gait was strange, rolling, but she kept up as long as Rachel held her howler to the power plant’s twenty KPH.

She could not grasp interstellar distances. Rachel didn’t push. She spoke of wonders instead: of the rings of Saturn, and the bubble cities of Lluagor, and the Smithpeople, and the settling of whale and dolphin colonies in strange oceans. She spoke of time compression: of gifting Sereda with designs for crude steam engines and myriads of wafer-sized computer brains, and returning to find steam robots everywhere: farmland, city streets, wilderness, households, disneylands; of fads that could explode across a planet and vanish without a trace, like tobacco pipes on Koschei, op-art garments on Earth, weight lifting on low-gravity Horvendile.

It was long before she got Gimpy talking about herself.

“I was of my parent’s second litter, within a group that moved here to study your kind,” Gimpy said. “They taught us bow and arrow, and a better design of shovel, and other things. We might have died without them.”

“The way you said that: second litter. Is there a difference?”

“Yes. One has the first litter when one can. The second litter comes to one who proves her capability by living that long. The third litter, the male’s litter, comes only with the approval of one’s clan. Else the male is not allowed to breed.”

“That’s good genetics.” Rachel saw Gimpy’s puzzlement. “I mean that your custom makes better fuxes.”

“It does. I will never see my second litter,” Gimpy said. “I was young when I made my mistake, but it was foolish. The breed improves. I will not be a one-legged male.”

They moved into a rift in the eroded mountain range, and the incredible became obvious. The mountains were topped with pink cotton candy. It must have been sticky like cotton candy, too. Rachel could see animals trapped in it. Gimpy wanted no part of that. She dropped back and boarded the raft.

They crossed the cotton candy with fans blasting at maximum. The big vehicles blew pink froth in all directions. Something down there wasn’t trapped at all. A ton of drastically flattened pink snail, with a perfect snail shell perched jauntily on its back, cruised over the cotton candy leaving a slime trail that bubbled and expanded to become more pink froth. It made for the still corpse of a many-limbed bird, flowed over it, and stopped to digest it.

The strangeness was getting to Rachel; and that was a strange thing for her. She was a rammer. Strangeness was the one constant in her life. Born aboard a ramship, not Morven, she had already gone once around the trade circuit. Even a rammer who returned to a world he knew must expect to find it completely changed; and Rachel knew that. But the strangeness of Medea came faster than she could swallow it or spit it out.

She fiddled with the intercom until she got Grace.

“Yes, dear, I’m driving. What is it?”

“It’s confusion. Grace, why aren’t all planets like Medea? They’ve all got domains, don’t they? Deserts, rain forests, mountains, poles and equators…you see what I mean?”

She heard the xenobiologist’s chuckle. “Dear, the Cold Pole is covered with frozen carbon dioxide. Where we’re going it’s hotter than boiling water. What is there on the trade circuit worlds that splits up the domains? Mountain ranges? An ocean for a heat sink? Temperature, altitude, rainfall? Medea has all of that, plus the one-way winds and the one-way ocean currents. The salinity goes from pure water to pure brine. The glaciers carry veins of dry ice heatward, so there are sudden jumps in the partial pressure of carbon dioxide. Some places there are no tides. Other places, Argo wobbles enough to make a terrific tidal slosh. Then again, everything has to adapt to the flares. Some animals have shells. Some sea beasts can dive deep. Some plants seed, other grow a big leaf for an umbrella.”

Beyond the pass the mountains dropped more steeply, down to an arm of the Ring Sea. Rachel had no problem controlling the howler, but the mobile power plant was laboring hard, with its front vents wide open to hold it back and little pressure left for steering. There should be no real danger. Two probes had mapped this course.

“Everything is more different, huh?”

“Excuse me, dear…that’s got it. Sonofabitch, we could live without that sonofabitching tail wind. Okay. Do you remember the mock turtle we showed you yesterday evening? We’ve traced it six thousand kilometers to coldward. In the Icy Sea it’s seagoing and much larger. Follow it heatward and it gets smaller and more active. We think it’s the food supply. Glaciers stir up the bottom, and the sea life loves that. To heatward a bigger beast starves…sometimes. But we could be wrong. Maybe it has to conserve heat in the colder climates. I’d like to try some experiments someday.”

The white boulders that turned out to be giant eggs were thicker here on the heatward slopes. And on the lower slopes— But this was strange.

The mountainsides were gay with pennants. Thousands of long, flapping flags, orange or chrome yellow. Rachel tried to make it out. Grace was still talking; Rachel began to feel she’d opened a Pandora’s Box.

“The closer you look to the Hot Pole, the more competition you find among the sea life. New things flow in from coldward, constantly. All the six-limbed and eight-limbed forms, we think they were forced onto the land, kicked out of the ocean by something bigger or meaner. They left the ocean before they could adopt the usual fish shape, which is four fins and a tail.”

“Grace, wait a minute, now. Are you saying…we…”

“Yes, dear.” The smile Rachel couldn’t see had to be a smirk. “Four limbs and a