Steller's Sea Cow

Steller's sea cow died twice. The hunting killed individuals—seven times the sustainable harvest rate, according to modeling studies. But the ecosystem collapse killed the species. When fur traders exterminated sea otters from the Commander Islands in the 1750s, they triggered a trophic cascade that doomed the sea cows even before hunters finished them off.

The cascade worked like this: sea otters eat sea urchins. Remove otters, and urchin populations explode. Urchins devour kelp. Kelp forests collapse into urchin barrens—underwater deserts. Steller's sea cow was an obligate kelp feeder, so buoyant it couldn't dive and had to browse the surface canopy. When the kelp disappeared, so did the food supply.

Discovered by Europeans in 1741 and extinct by 1768, this marine mammal achieved the fastest recorded extinction of any large animal at human hands—27 years from first contact to last individual. Growing up to 10 meters long and weighing 10 tonnes, sea cows had no fear of humans and were easy to hunt. Their meat fed expeditions; their fat fueled lamps; their hides covered boats.

But direct hunting wasn't the only killer. Research suggests that even if hunting had stopped, the kelp collapse would have starved the remaining population within decades. The sea cows depended on an ecosystem infrastructure they didn't create and couldn't maintain. When the keystone species (sea otters) disappeared, everything that depended on the kelp forest faced existential threat.

The business parallel is stark: companies dependent on platform ecosystems face similar cascade risks. When Apple introduced App Tracking Transparency in 2021, it cascaded: Apple policy → Facebook ad effectiveness dropped 30-50% → ad revenue declined billions → CPMs fell → identity graph companies collapsed. Four levels of cascade from one policy change.

Steller's sea cow couldn't have known that its survival depended on sea otters. The connection was invisible—mediated through urchins and kelp, species the sea cow never interacted with directly. Similarly, businesses often don't recognize their keystone dependencies until collapse reveals them. The restaurant that depends on Yelp reviews, which depend on Yelp's search ranking, which depends on Google's algorithm, faces three levels of invisible dependency.

K-selected species like sea cows—large, slow-reproducing, long-lived—are particularly vulnerable. They cannot recover quickly from population crashes. A sea cow pregnancy lasted over a year; calves nursed for years more. Unlike r-selected species that can explode back from a few survivors, K-selected populations decline in a death spiral once pushed below viable breeding numbers.

The lesson: in interconnected systems, your survival depends not just on your direct resources but on the health of keystones you may never see. The sea cow's fate was sealed not when the hunters arrived, but when the otters disappeared.