from the world's big
Love avocados? Thank the toxodon
Avocado evolved in the warming climates of Central America during the Neogene period, roughly 10 million years ago.
Given avocado's popularity today, it's hard to believe that we came close to not having them in our supermarkets at all.
In my new book “Avocado: A Global History," I explain how the avocado survived a series of ecological and cultural close calls that could have easily relegated them to extinction or niche delicacy. Instead, the avocado persevered, prospered – and became one of the most Instagrammed foods in the world.
A 'ghost of evolution'
Avocados are in the laurel family, the same group of plants that includes bay leaves and cinnamon. Laurel trees prosper in warm subtropical climates, and the avocado evolved in the warming climates of Central America during the Neogene period, roughly 10 million years ago.
During the Pleistocene era, which followed the Neogene, the biggest animals on Earth were what we call the megaherbivores – giant animals that subsisted almost entirely on a vegetarian diet. Most of these, like the giant ground sloth, would have dwarfed today's largest megaherbivore, the African elephant. The giant herbivores of Pleistocene Mesoamerica like the gomphothere, the giant armadillo and the toxodon needed hundreds of pounds of food a day just to survive. Since food like leaves and grasses are so low in calories and fat, the animals prized any energy dense and fatty foods.
Enter: the avocado.
Megaherbivores didn't peel the avocados and eat the green meat like we do today. Instead, their throats and digestive tracts were so large that they would simply swallow the avocado whole and excrete the undigested pit. In a process known as endozoochory, the pile of manure would serve as food for the next generation of avocado trees. As these giant animals roamed and grazed on avocados, they spread the fruit across what is now central Mexico.
Megaherbivores like the toxodon were the avocado's best friend. (Robert Bruce Horsfall/Wikimedia Commons)
But once the megaherbivores died off, the fruit was in a bind. The herbivores that were left had throats far too small to ingest a whole avocado seed, and dropping a giant seed at your own roots is a poor survival strategy for a tree; to thrive, it needs to disperse more broadly.
Avocados became what the botanist Connie Barlow calls a "Ghost of Evolution" – a species that should have gone extinct but was somehow able to survive. What the avocado had going for it was the lifespan of its trees, which survive much longer than most fruit trees. There are 100-year-old trees still producing fruit in California and 400-year-old trees in central Mexico.
By living so long and being so well adapted to their ecological niche, avocados were able to hold on until their next dispersers – Homo sapiens – came along.
More stops and starts
The earliest humans in Mesoamerica were quick to appreciate the virtues of the avocado. Groups like the Olmecs and the Maya started the first avocado orchards and began cultivating specimens that tasted the best and had the meatiest fruits, a process of trait selection that gave us the kinds of avocados we love today. Avocados were so important to the Maya that the 14th month of their calendar was named for them.
In the 1830s, Floridian Dr. Henry Perrine was introduced to avocados while serving as U.S. consul in Campeche, Mexico, and thought they would be an excellent addition to Florida's horticultural offerings.
He sent some seeds to a friend on Indian Key in Florida who planted them. Not long after Perrine returned, the Second Seminole War broke out. Perrine and his family sought shelter from the fighting on the key, but he was killed during a raid on the island by one of the warring factions. The island was abandoned and the avocado trees were forgotten.
Hot and humid Florida had been hospitable to the avocado, but California has enough cold snaps in the winter months to make it difficult for most avocado varieties to thrive there. This could have been another dead end for the fruit, but early settlers in California took another stab at establishing them in the U.S. After a few failed attempts in the 1850s and 1860s, grower Judge R. B. Ord obtained a few cold-hardy specimens from central Mexico. A cold-tolerant variety was needed if California was to have a profitable avocado industry. Without it, the avocado might have remained a delicacy local to Mexico and its neighbors.
One of the earliest cold-hardy specimens was a variety given the name "Fuerte," which means "strong" in Spanish. The Fuerte avocado earned its name because it was one of the few varieties that survived the famous "Freeze of '13," a spell of cold weather that nearly ruined the nascent fruit industries of Southern California in the winter of 1913.
Until the 1940s, the Fuerte was the most popular avocado variety in America and made up about 75% of avocados sold.
The Hass comes to pass
The Fuerte has since been relegated to niche product, and represent only about 2% of the California market. Instead, the lion's share of avocados sold today are the variety known as Hass, which rhymes with "pass."
But were it not for a couple of kids with precocious palates, the world may never have tasted a Hass avocado, with the fruit remaining an odd delicacy for the well-to-do.
The Hass avocado is named for Rudolph Hass, a mailman who lived in La Habra, California. Originally from Milwaukee, Hass joined the thousands of Americans who went west to California in the 1920s and 1930s.
After reading a brochure about the money to be made in avocado ranching, he borrowed enough money to buy a small plot of land with Fuerte avocado trees on it. In the late 1920s, Hass bought some avocado seeds to grow rootstock for his budding nursery. One of these seeds grew a funny tree that rejected the Fuerte limbs that Hass wanted to graft onto it – a process that involves combining two tree plants with distinct characteristics. He was about to cut the misbehaving tree out, but his kids told him that these odd little avocados were their favorites, so he relented and kept the tree. After trying them himself, he thought they had marketing potential and began selling them to people at work and at a market in town.
Hass avocados slowly caught on, and in 1935 Hass patented the tree, the first patent awarded for a tree in America. But most growers, instead of buying his tree, evaded his patent and simply grafted their cuttings themselves. This practice was illegal, but enforcement in the 1930s was spotty.
Today, Americans eat 100 million pounds of avocados on Super Bowl Sunday, and Hass should have died a rich man. But he never earned enough to quit the post office, and it's estimated that he only made about US$5,000 on the patent in his lifetime.
- The ketogenic diet may help fight against the flu - Big Think ›
- Scientists create avocado that stays ripe longer - Big Think ›
Emotional intelligence is a skill sought by many employers. Here's how to raise yours.
- Daniel Goleman's 1995 book Emotional Intelligence catapulted the term into widespread use in the business world.
- One study found that EQ (emotional intelligence) is the top predictor of performance and accounts for 58% of success across all job types.
- EQ has been found to increase annual pay by around $29,000 and be present in 90% of top performers.
Evolution doesn't clean up after itself very well.
- An evolutionary biologist got people swapping ideas about our lingering vestigia.
- Basically, this is the stuff that served some evolutionary purpose at some point, but now is kind of, well, extra.
- Here are the six traits that inaugurated the fun.
The plica semilunaris<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwMS9vcmlnaW4ucG5nIiwiZXhwaXJlc19hdCI6MTYxMTgyMzg1NX0.ZY8qmhtoZfbRMAqrNnmbgyk7GLabglx_9lBq3PKcy7g/img.png?width=980" id="99882" class="rm-shortcode" data-rm-shortcode-id="68e8758894b0359c6ef61b2c158832b2" data-rm-shortcode-name="rebelmouse-image" />
The human eye in alarming detail. Image source: Henry Gray / Wikimedia commons<p>At the inner corner of our eyes, closest to the nasal ridge, is that little pink thing, which is probably what most of us call it, called the caruncula. Next to it is the plica semilunairs, and it's what's left of a third eyelid that used to — ready for this? — blink horizontally. It's supposed to have offered protection for our eyes, and some birds, reptiles, and fish have such a thing.</p>
Palmaris longus<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgwNy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzMzQ1NjUwMn0.dVor41tO_NeLkGY9Tx46SwqhSVaA8HZQmQAp532xLxA/img.jpg?width=980" id="879be" class="rm-shortcode" data-rm-shortcode-id="970e9c15f3c3d846dde05e2b2c6ebf12" data-rm-shortcode-name="rebelmouse-image" />
Palmaris longus muscle. Image source: Wikimedia commons<p> We don't have much need these days, at least most of us, to navigate from tree branch to tree branch. Still, about 86 percent of us still have the wrist muscle that used to help us do it. To see if you have it, place the back of you hand on a flat surface and touch your thumb to your pinkie. If you have a muscle that becomes visible in your wrist, that's the palmaris longus. If you don't, consider yourself more evolved (just joking).</p>
Darwin's tubercle<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NjgxMi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY0ODUyNjA1MX0.8RuU-OSRf92wQpaPPJtvFreOVvicEwn39_jnbegiUOk/img.jpg?width=980" id="687a0" class="rm-shortcode" data-rm-shortcode-id="b38a957408940673ccc744f0f6828d18" data-rm-shortcode-name="rebelmouse-image" />
Darwin's tubercle. Image source: Wikimedia commons<p> Yes, maybe the shell of you ear does feel like a dried apricot. Maybe not. But there's a ridge in that swirly structure that's a muscle which allowed us, at one point, to move our ears in the direction of interesting sounds. These days, we just turn our heads, but there it is.</p>
Goosebumps<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNzEyNTc2Nn0.aVMa5fsKgiabW5vkr7BOvm2pmNKbLJF_50bwvd4aRo4/img.jpg?width=980" id="d8420" class="rm-shortcode" data-rm-shortcode-id="f735418322b34382dcd882299c9ccc48" data-rm-shortcode-name="rebelmouse-image" />
Goosebumps. Photo credit: Tyler Olson via Shutterstock<p>It's not entirely clear what purpose made goosebumps worth retaining evolutionarily, but there are two circumstances in which they appear: fear and cold. For fear, they may have been a way of making body hair stand up so we'd appear larger to predators, much the way a cat's tail puffs up — numerous creatures exaggerate their size when threatened. In the cold, they may have trapped additional heat for warmth.</p>
Tailbone<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMxNi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMDMzMDc3N30.p9BEtkf3-PV3EtDSQMUGUeopsimiCHUagx97P4f8IBw/img.jpg?width=980" id="e8ab8" class="rm-shortcode" data-rm-shortcode-id="0063ce99bdd22fbebe1279244b87935c" data-rm-shortcode-name="rebelmouse-image" />
Coccyx. Image source: decade3d-anatomy online via Shutterstock<p>Way back, we had tails that probably helped us balance upright, and was useful moving through trees. We still have the stump of one when we're embryos, from 4–6 weeks, and then the body mostly dissolves it during Weeks 6–8. What's left is the coccyx.</p>
The palmar grasp reflex<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8xOTA5NzMyMC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjY0MDY5NX0.OSwReKLmNZkbAS12-AvRaxgCM7zyukjQUaG4vmhxTtM/img.jpg?width=980" id="8804c" class="rm-shortcode" data-rm-shortcode-id="45469ca5ee5f43433a782f7d4ac0a440" data-rm-shortcode-name="rebelmouse-image" />
Palmar reflex activated! Photo credit: Raul Luna on Flickr<p> You've probably seen how non-human primate babies grab onto their parents' hands to be carried around. We used to do this, too. So still, if you touch your finger to a baby's palm, or if you touch the sole of their foot, the palmar grasp reflex will cause the hand or foot to try and close around your finger.</p>
Other people's suggestions<p>Amir's followers dove right in, offering both cool and questionable additions to her list. </p>
Fangs?<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Lower mouth plate behind your teeth. Some have protruding bone under the skin which is a throw back to large fangs. Almost like an upsidedown Sabre Tooth.</p>— neil crud (@neilcrud66) <a href="https://twitter.com/neilcrud66/status/1085606005000601600?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Hiccups<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Sure: <a href="https://t.co/DjMZB1XidG">https://t.co/DjMZB1XidG</a></p>— Stephen Roughley (@SteBobRoughley) <a href="https://twitter.com/SteBobRoughley/status/1085529239556968448?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Hypnic jerk as you fall asleep<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">What about when you “jump” just as you’re drifting off to sleep, I heard that was a reflex to prevent falling from heights.</p>— Bann face (@thebanns) <a href="https://twitter.com/thebanns/status/1085554171879788545?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script> <p> This thing, often called the "alpha jerk" as you drop into alpha sleep, is properly called the hypnic jerk,. It may actually be a carryover from our arboreal days. The <a href="https://www.livescience.com/39225-why-people-twitch-falling-asleep.html" target="_blank" data-vivaldi-spatnav-clickable="1">hypothesis</a> is that you suddenly jerk awake to avoid falling out of your tree.</p>
Nails screeching on a blackboard response?<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Everyone hate the sound of fingernails on a blackboard. It's _speculated_ that this is a vestigial wiring in our head, because the sound is similar to the shrill warning call of a chimp. <a href="https://t.co/ReyZBy6XNN">https://t.co/ReyZBy6XNN</a></p>— Pet Rock (@eclogiter) <a href="https://twitter.com/eclogiter/status/1085587006258888706?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Ear hair<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Ok what is Hair in the ears for? I think cuz as we get older it filters out the BS.</p>— Sarah21 (@mimix3) <a href="https://twitter.com/mimix3/status/1085684393593561088?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Nervous laughter<blockquote class="twitter-tweet" data-lang="en"><p lang="en" dir="ltr">You may be onto something. Tooth-bearing with the jaw clenched is generally recognized as a signal of submission or non-threatening in primates. Involuntary smiling or laughing in tense situations might have signaled that you weren’t a threat.</p>— Jager Tusk (@JagerTusk) <a href="https://twitter.com/JagerTusk/status/1085316201104912384?ref_src=twsrc%5Etfw">January 15, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Um, yipes.<blockquote class="twitter-tweet" data-conversation="none" data-lang="en"><p lang="en" dir="ltr">Sometimes it feels like my big toe should be on the side of my foot, was that ever a thing?</p>— B033? K@($ (@whimbrel17) <a href="https://twitter.com/whimbrel17/status/1085559016011563009?ref_src=twsrc%5Etfw">January 16, 2019</a></blockquote> <script async src="https://platform.twitter.com/widgets.js" charset="utf-8"></script>
Are there innate differences between female and male brains?
People have searched for sex differences in human brains since at least the 19th century, when scientist Samuel George Morton poured seeds and lead shot into human skulls to measure their volumes.
This course collection can get you trained and ready for a six-figure career in this field.
- The Premium 2020 Project & Quality Management Certification Bundle explores the most popular project management methodologies.
- Coursework covers Agile, Agile Scrum, PMI-PMBOK and Six Sigma approaches.
- Valued at $2,699, the course package is on sale for just $45.99.