Florida's gentle giants, the manatees, are dying in alarming numbers

Nov 29, 2022

Some 50 million years ago, a pig-like, four-legged animal species that a scientist once described as looking like a cross between a hippopotamus and an otter evolved and entered the water. We know them now as manatees, but due to their herbivorous diet and docile behavior, they are also known as sea cows.

Natural selection favored the manatees with larger bodies, which let an animal store heat, and slow metabolism, which forced the animals to use less energy swimming around and consuming their sole diet of plants. Aside from sharks, considered a rare exception, the manatee had no natural predators. Nor did these enormous animals ever hunt prey throughout their long evolution.

Therefore, even if the animal's size was advantageous, these gentle vegetarians did not need sophisticated sensory systems and varied, complex behaviors found in many other larger mammals. Instead, all the 3,000-pound animal requires is a tiny brain about the size of a grapefruit. And it's a smooth brain; it doesn't need the intricate folded structure found in the brains of other mammals. Of course, all this has led to a reputation for not being very clever mammals, but like every animal, it is challenging to make assumptions about its intelligence.

Measuring intelligence

Turning the assumption of intelligence around, let's consider a scientist bee who studies humans. Bees respond to infrared light; therefore, this cunning bee tests human intelligence to see how humans react to various types of this light. Unfortunately, the bee doesn't understand that we can't see infrared light, and it thus concludes that we are far less intelligent than bees. (The scientist bee may be wrong here, but it's an understandable assumption made by the bee after witnessing humans exterminate billions of its fellow bees. Furthermore, our clever bee knows that humans depend on bees to pollinate much of the food we require. The bee is forgiven for thinking we are rather foolish.)

Additional studies may provide more information about the manatee's brain, which may be more sophisticated than their outward look would imply. Although their brains appear smooth on the outside, the inside is highly intricate. Several significant clusters of nerve cells in their cerebral cortex are probably directly related to the manatee's antenna-like hairs, a highly evolved sense that we may only begin to understand. Maybe we should examine their growth and abilities from a new angle and avoid the example of our scientist bee who jumped to the wrong conclusion about humans. After all, manatees have existed in this world much longer than we have.

Endangered

The bad news is that the survival of these gentle giants is far from certain. They may not survive due to our interference with their habitats. And that's so sad; I love watching these good-natured mammals who have never hurt anyone and genuinely care for their young. But, unfortunately, the hearts of the manatee parents must break each time their offspring are struck by boat propellers.

Mother manatee and calf (photo: Sam Farkas)

The West Indian manatee is divided into two subspecies; the Florida manatee (T. m. latirostris) and the Caribbean manatee (T. m. manatus). The Florida manatees are hit so frequently that researchers can recognize them by the pattern of their scars.

Florida Manatees were downlisted from an endangered species to the less severe category of threatened species five years ago. In retrospect, that was a poor choice. Since then, their numbers have decreased, particularly in the past two years. Following the nearly 2,000 manatee deaths in Florida's coastal and interior waters over the past two years, a coalition of environmental organizations has called for the species to be urgently reclassified as endangered.

A 19 percent drop in numbers in just two years

Manatees experience habitat loss, boat hits, becoming entangled in marine debris, algal blooms, fertilizer runoff from leaking septic systems, and eating plastic or other pollution. And add to all these threats another man-made scourge: climate change that threatens the manatees by acidification, sea level rise, and extreme weather. In the past two years, the Atlantic population of Florida manatees dropped by a staggering 19 percent.

It's sad to see yet another instance of a unique species going through hardships and facing extinction after millions of years of gently living a quiet vegetarian life without bothering anyone. The authorities should take every precaution possible to save the manatees; they are vital to the ecosystem. We have seen in the past what a higher level of protection can do for the species' survival. The knowledge is there; as we have seen so often, it's ultimately about the political will to prioritize life on the planet.

If you got this far, please read this too:

I write this newsletter because I believe we can do better on this beautiful but fragile planet.
Please consider supporting this initiative by taking a paid subscription. We need your help to continue making this newsletter available to everyone.