800 kilometres across Yellowstone National Park

This earth originates from the greatest depths, yet it is newer than everything around us. In Yellowstone, we stand inside the caldera of an active volcano; the ground bubbles and steams. The heat from beneath gives the region its trademark feature: its colours. Yet in the end, that wasn’t the most fascinating part in this leg of the journey.

KM 900, 2.1 million years ago

First, however, a brief jump back in time; for Yellowstone is past and present all at once.

2.1 million years ago the Earth saw the birth and largest eruption to date of the Yellowstone volcano: the Huckleberry Ridge eruption. Two further eruptions followed. The last outbreak, which actually contributed to the caldera’s current shape, occurred just 640 000 years ago, known as the Lava Creek eruption.

We slowly drive into the park, approaching from the south directly from Grand Teton National Park. The road winds uphill. Behind us, a never-ending tailback of cars struggles up the slope. At over 2000 metres, the Land Cruiser’s engine no longer delivers much power, especially when climbing, so we push forward slowly yet steadily at 40 km/h. We quietly enjoy the landscape and keep an eye out for wildlife. The enthusiasm of the drivers behind us, who are taking the brunt of our black exhaust fumes, seems rather limited by comparison.

Lewis Falls comes into view, the river meanders through the tuff just like the road. Tuff is a rock formed from consolidated volcanic ash and pyroclasts. Reaching the ridge above, we stand at the edge of a round basin. Yet unlike so many volcanoes we have visited across the continent, we see neither a beginning nor an end at Yellowstone.

Yellowstone’s volcanic caldera measures 48 by 72 kilometres. Beneath the caldera lies a hotspot, the point where hot mantle material rises from deep within the Earth. The ridge we crest every time we drive through Yellowstone Park is the rim of the supervolcano. Below it bubbles a massive magma chamber, and its enormous forces can be felt all the way to the surface. At such hotspots, the Earth’s surface regenerates from ancient, molten rock. And this plateau rises and falls by several centimetres every year.

We have arrived in the present of our journey: where stone comes to life.

Some elements of a typical volcanic landscape are visible to the naked eye. Over 10 000 hydrothermal features shape the terrain. Geysers vent steam as if mini-factories were at work everywhere. Mud pots bubble away, and bison warm themselves on nature’s underfloor heating. Other features can only be felt: thermal springs warm the rivers to the perfect temperature for fish. And in winter, the interior of the caldera shelters a warm zone here and there where animals can escape the deepest snow.

And then there are the living organisms that only truly thrive in near-boiling water: thermophilic microorganisms. They not only withstand boiling water, but also feel right at home in extreme acidity. However, they like it hot but do not tolerate temperature shifts. In the hottest water live mainly transparent and yellow microbes, with the transparent ones glowing blue to the human eye. Along the cooler edges, orange, brown, and green groups gather. Together, they create an impressive, colourful, living spectacle.

Yellowstone National Park covers an area of nearly 9 000 square kilometres—2.5 times the size of Mallorca. Established in 1872, it is considered the first official national park in the world. However, the welcome news of nature conservation had a dark prelude—for animals and humans alike.

We drive along the Chief Joseph Scenic Byway over Dead Indian Pass towards the North East Entrance of Yellowstone National Park. The tragic name of the pass stems from the displacement of Native Americans from their ancestral lands. The Nez Perce fled from the Yellowstone mountains to the Great Plains during the Nez Perce War of 1877. In doing so, they outsmarted the US Army: they led them to believe they were taking the easier southern route. Instead, they climbed the steep pass. By the time the soldiers realised, the Nez Perce were gone. Apparently, however, a Nez Perce was ultimately killed on the pass—giving Dead Indian Pass its name.

The region around the Rocky Mountains was inhabited by various Indigenous groups. For a long time, they were tolerated in these barren and challenging areas because settlers were slow to reach them. Originally, the concept of a “national park” arose in the early 19th century as a place where Native Americans could maintain their traditional way of life. But the idea shifted: Native Americans were forced onto Indian reservations, and from the national parks emerged the dream of creating an untouched wilderness. Until then, the American wilderness was viewed merely as a vast, lawless hunting ground.

What has become of this wilderness is something we want to see with our own eyes.

On the road with stragglers, leaping pupils and a rather skinny giant off Baja California

We are almost too late – and we feel it, too. But well, we are only almost too late. Most of the grey whales have already moved on by the time we arrive in the bay of Bahía La Almeja. The fisherman takes us out anyway. To where the sea flows into the bay. On the off chance, maybe one of these whales will show up after all.

The grey whale that is a straggler

During the summer months, the grey whales dedicate themselves to feeding in the nutrient-rich Bering Sea. But they spend the winter months in the warmer waters of Baja California. They give birth to their calves in the bays, because there they are protected from killer whales.

We head out to the entrance of the bay at full throttle. Long ocean rollers stretch along the coast towards Santa Margarita Island. In the middle, you can barely feel the swell, until a larger wave breaks prematurely after all. Our captain is constantly keeping watch – for the whales and for the waves.

Meanwhile, the peak season for humpback whales is in full swing. Along the southern coast of Baja California, splashing and slapping hits the water from all sides. The young calves are learning to leap, and the adults have to show them how it’s done.

Humpback whales can be found in all the world’s oceans. We have encountered them in Central America before, but we didn’t experience a spectacle quite like the one in Baja California there. The days fly by – or disappear with the current – as we look out at the water, constantly keeping watch for the active giants.

The calves, barely five metres long, are still acting clumsily, while the mother, nearly three times their size, literally catapults herself out of the water. A splash that we can still hear a kilometre away on the beach. The exact reason for the whale breaches is unexplained; it could be against parasites, as play, or for communication. But if that isn’t loud enough, they slap their fins. Individual slaps with the pectoral fin or the fluke onto the water’s surface sound almost like a belly flop from a three-metre diving board.

A song without end

Once we’ve seen more than enough from the beach, we venture out onto the water by boat. Ideally, we would have paddled out directly on our own SUPs or something similar, but there was nothing to be found. And there it is again: mother and calf swimming peacefully along with the currents. Every now and then, a male joins them. Mostly, they are tolerated by the mother cows for protection against killer whales. Because orcas simply like young whale calves – their favourite part is the tongue.

Humpback whales are also present underwater. Albeit far enough away that they can’t be seen, they can certainly be heard. Thanks to a specially shaped larynx, humpback whales can reuse once-inhaled air over and over again to perform long songs. Yes, exactly, entire songs – even with recurring verses. And they learn them from an early age, so that the same population sings the same song – despite the annual adaptation of the hit.

The clock that urges us to continue on

For hours – if not days – we gaze out into the water. The whales, dolphins, rays and fish, the sea lions and sea turtles, the seabirds and crabs provide the best entertainment. Boredom never strikes; it is only time that flies by in a whirlwind. The clock is ticking; it is time to move on.

It is with a heavy heart that we leave the beautiful beaches of southern Baja California. We set off in search of other giants, namely those from the world of plants. To do so, we must swap salt for dust. Fortunately, we know that at our destination, a plunge into the cold sea water awaits us once more.

Then it simply swims past me. The first metre: leathery skin up to ten centimetres thick, speckled with bright little dots like water droplets. This pattern is as unique to each animal as a human fingerprint. Two, three, four metres. There fish still hasn’t passed me. Five, six, seven metres. The tail fin, as tall as a human, glides past me.

And just like that, the massive whale shark has vanished back into the murky sea. I swim after it, which requires a fair amount of stamina. Fortunately, I am wearing fins, otherwise I would hardly be able to keep up with its leisurely cruising speed of about 5 km/h.

Baja California and especially the Sea of Cortez resemble a cold, gargantuan aquarium. We spend all day at a wide variety of beaches – even the annoying sand that constantly steals into the inside of the car is absolutely worth it.

We are constantly looking out at the water. You must not let yourself get distracted, because you regret it instantly. Right by the shore, pelicans and ospreys crash headfirst into the surface in a steep dive to grab their snack and immediately safeguard it from the gulls.

Out on the horizon, sometimes near, sometimes far, a humpback whale calf practises its first, rather clumsy breaches, while the mother right beside it elegantly demonstrates how it is done. No sooner has the whale submerged than dolphins leap past, and shortly before sunset, more and more mobula rays catapult themselves out of the water like skipping stones. In between, a sea lion pops up briefly or a sea turtle comes to the surface to breathe. You quite simply have no chance of getting enough of it.

Only in the evening, when everything is dark, does it seem the right time for a break. Until a loud splash on the water somewhere serves as a reminder: the whales are still swimming past.

A small stream winds its way under the bridge, losing itself in the stony, rugged terrain. A simple archway marks the entrance to the recreation area. The ticket booth – a small, rather dilapidated hut – looks deserted. Although the price is posted (5 pesos per person), there is no one in sight to collect the money.

The only neighbour in sight seems to be driving away. I manage to flag her down. ‘The owners are at a party and won’t be back until tomorrow,’ she explains. She adds that it should be absolutely fine if we just stay. Is this our free pass for an overnight stay?

Despite the nearby main road – the only thoroughfare through this area – the spot feels idyllic. Conifers and oaks frame the meadow, and the stream babbles over the rocks with such consistency that small, natural pools have formed over time. There are fire pits and benches.

We knew that we were highly unlikely to find the extremely rare Ambystoma mexicanum here. Yet the mole salamander family has other fascinating members. In Mexico, the word axolote is often used as a general term for salamanders that remain in their larval stage. Many of these species possess the ability of neoteny: they reach sexual maturity without ever shedding their larval form (gills included).

One such species is the plateau tiger salamander (Ambystoma velascii).

Metamorphosis on demand

In the larval stage, the true axolotl and the tiger salamander are barely distinguishable. This often leads to wild-caught A. velascii being mistakenly sold as axolotls. The surprise usually follows in the aquarium: while the true axolotl almost always remains a “child”, the tiger salamander undergoes a complete metamorphosis as soon as conditions (such as water levels or temperature) change. It loses its gills, develops lungs, and leaves the water as a terrestrial salamander.

In the river system where we ended up, however, they apparently remain in the water for life. This usually happens at higher altitudes when they grow up in a body of water free from predatory fish. And that is exactly where we finally find them: tiny, dragon-like creatures with four legs and the characteristic crown of gills. It takes a while before we spot the first specimen in the somewhat murky water, but then we see them everywhere – in all sizes, completely undisturbed in their idyllic world.

When we drive past the ticket booth the next morning to pay, we are met with astonished glances. The owners hadn’t even noticed that anyone had been camping down by the river. To them, the axolotes are simply neighbours in the stream – to us, it was an encounter with yet another wonder of nature.

Snakes and other reptiles in Mexico – Part II

One swings the lasso, the next takes over if the first throw misses, and a third, armed with a stick, stands guard to ensure the crocodile doesn’t get too close. We intend to catch it, certainly, but contact should only occur on our terms – when it is safe for both human and animal.

That might sound sarcastic; after all, a crocodile is always dangerous. Yes, absolutely. But even these animals can be handled with varying degrees of risk. Since we are currently in Mexico, Michael decided it was the perfect place to learn something new. By chance, he stumbled upon a crocodile-handling course. And, well, why not give it a go?

Even the tamest of animals can be dangerous depending on the situation. With these massive reptiles, the peril is staring you right in the face. Since Michael had already caught small caimans by hand in Bolivia, we now want to learn how the larger specimens are managed using proper equipment.

A Star of Herpetology

Most animals are released back into the wild as soon as they are healthy and capable of survival. Some must stay forever. Take the American Crocodile Canelo, who suffered a broken jaw due to mistreatment; he can no longer open his mouth further than 10 cm and is therefore unable to hunt. Some birds had their wings clipped; for them, freedom would mean certain and immediate death. Or some animals have been imported and are not endemic to the nature, thus can not be set free.

Jeronimo began his career as a biologist counting crocodiles. It is partly thanks to his analyses that protected areas were established and laws passed to safeguard wild populations. It may sound cynical, but the fact that crocodiles can be kept legally on farms for meat and leather production has actually aided wild stocks. These farms are only permitted to operate as long as a minimum population thrives in the wild. Consequently, poaching has plummeted, and species like the Morelet’s crocodile have been removed from the Red List of threatened species.

To further reduce stress, we place a cloth over their eyes. When they cannot see, their entire system shuts down. In this instinctive survival mode, they power down their metabolism—one of many tactics these masters of adaptation have perfected over 200 million years. One of the anatomical wonders is the actively controlled Foramen of Panizza in the right ventricle of the heart. Under water, they can close this valve, preventing blood from being shunted to the lungs. Deoxygenated blood bypasses the lungs and flows directly back into the systemic circulation and to the stomach. This not only allows them to dive for longer but also aids digestion due to the more acidic blood.

Teamwork or couple’s therapy?

With large crocodiles, two hands are no longer enough. This is where lassoing and precise teamwork come into play. From a distance, ropes are used to hold the jaws shut. Crocodiles possess immense biting power, yet they have almost no muscle strength to open their mouths against resistance.

It takes practice to hit the mark, but it works. Then we haul it onto land, where two people secure it. The approach starts at the tail and moves toward the head; you then pin the front legs with your knees and apply pressure to the back without sitting fully on it. A second person does the same with the hind legs.

The skin feels like cool, embossed leather—firm, dry, and surprisingly clean. Once secured, measurements are taken. To weigh the animal, it is trussed up; though it looks barbaric, it is for the safety of everyone involved. Once everything is done, we release it back into the enclosure. This is one of the most dangerous moments.

Despite the knotting technique, a residual risk remains: the crocodile feels the moment the restraints fall and fights back. Michael ends the day with grazed hands from his rodeo ride on the reptile. Our two American crocodile specimens weighed about 80 kg and were over 2.5 metres long; four people were needed to lift them. The largest specimen, Argos, at over 4 metres, would easily push eight people to their limits. We’ll leave that one for another time!

After two days, we say our goodbyes with grazed knees and bruised legs, but proudly holding our certificates as official “crocodile handling experts” in Mexico in our (mostly) intact hands.

Snakes and other reptiles in Mexico – Part I

As we fought our way through millions of bats in Kantemó to reach the hungry rat snakes, we had no idea that shortly afterwards, we would almost be carrying a rattlesnake as an involuntary hitchhiker.

It all begins in total silence. Despite the darkness of the cave, we know the sun hasn’t set yet. But the first few faint wingbeats soon multiply, growing louder and louder. They slice through and churn up the air, which thickens with the scent of guano. Our face masks are meant to protect us from health risks, yet the acrid stench penetrates every filter. The air in the cave vibrates palpably; millions of small mammals are seeking the exit to turn the night into their hunting ground.

The hanging snakes of Kantemó

That is where we must enter. Crouched and only with the pale glow of our torches, we struggle forward. To our left and right, the animals shoot past us, guided by their precise echolocation, which veers them away from our faces at the very last millisecond—most times, at least.

The deeper we venture, the more stifling the air becomes. We are surrounded by life; a fleeting thought of “Patient Zero” creeps in as the walls close in. But we are here for a very specific inhabitant: the yellow red ratsnake (Pseudelaphe flavirufa).

These animals are unique masters of adaptation. Unlike vipers, they do not possess thermal vision. They live in permanent darkness and have never seen daylight—and yet, they see. Their reddish, oversized eyes look like rubies in the torchlight, perfectly adapted for localising bats. The snake colony of Kantemó is estimated at about 100 individuals—a microcosm that survives by hunting bats mid-flight.

In March, the desert on the peninsula Baja California awakens. The air still blows cold from the sea, but the sun is already warming the ground. Amidst dust and thorny bushes, we encounter a different calibre: the rattlesnake.

Venemous snake handling: When Michael’s training saves the day

The rattle makes you shudder instinctively—a sound that goes right through you. We had almost run over a specimen; she was lying exactly between the wheels. Thanks to Michael’s training in handling venomous snakes, we are able to safely get the animal away from the road. All the while, she rattles incessantly with her keratin rattle at the end of her tail—a remnant of every single shed—letting us know she is dangerously venomous.

Rattlesnakes are pit vipers native only to the American continent—but found there from Argentina to Canada. It took us a while to see one, the first one not until Baja California: a Speckled Rattlesnake (Crotalus mitchellii). It was about time, considering most snakes of this species live in Mexico.

This feared species is found on the ground and usually sounds the alarm if you get too close, but when they bite, “dry bites” are rare. Their haemotoxic venom decomposes blood cells, leading to very painful internal bleeding, tissue destruction, and swelling. The only option then is to find a hospital quickly and hope they have antivenom in stock.

The snake winds itself beautifully around the tree trunk. Another poses on a lush green leaf, with the Arenal Volcano in the background. Simply incredible, the perfect coincidence – or is it?

We have often wondered how it is that animals in photos always pose so beautifully – mind you, wild animals.

The answer? It’s sobering: the animals are placed exactly where people want them.

The methods behind the photo

With cold-blooded animals, there are particularly questionable methods: when they are chilled, they hardly move. There are even reports of limbs being suspended by threads. A famous photo of a frog riding a beetle was likely staged this way, as the two species are not active at the same time of day.

Bringing a jaguar into the right position in the wild is difficult – if not impossible. To give tourists a guaranteed sighting, providers resort to aids. Feeding stations are far more common than one might think.

We have also been offered a guaranteed sighting of a “wild” ocelot, or taken to a feeding site for tapirs; even the Orinoco crocodile is fed regularly so that it remains within the national reserve and isn’t killed outside its borders.

Feeding stations for birds are found almost everywhere: Bananas and sugar water are popular choices.

As long as tour operators can guarantee sightings, their income is secure. This leads to a dangerous set of expectations. Tourists want “wildlife photos”. In Costa Rica, the practice went so far that sloths, for example, were taken down from trees just for a “wildlife selfie”. The government launched an awareness campaign in 2019. Perhaps it helped. We didn’t experience anything of this sort ourselves, but we read about it.

With snakes, however, we witnessed a different side of the story.

The business of “perfect” nature

In Costa Rica, we came across a particularly negative practice: a photographer told us about providers who carry snakes around in boxes to position them in the perfect spot. We also came across a post on Facebook denouncing this exact practice.

And why? Simply to offer tourists the perfect picture. It would quite frankly be too exhausting to spend the night in the jungle without a guaranteed find – plus, you can’t see the volcano at night.

Unfortunately, this practice is quite widespread – even in countries like Costa Rica, where animal welfare is supposedly a high priority. What can then be expected from other countries that hardly care about it at all?

Encounters with Costa Rica’s primates

We see “big monkeys” all the time – after all, we’re all guilty of making a monkey out of ourselves every now and then. But those that actually still swing through the treetops are, sadly, becoming fewer and farther between.

By now, we’ve reached the north of Central America, and here they have become a rare sight. Since crossing the border from Costa Rica, we haven’t spotted a single monkey – we haven’t even heard one. Reason enough to look back wistfully at our time in Costa Rica, where we were lucky enough to observe all four native monkey species, some of them on multiple occasions.

Capuchin: grumpy and intelligent

They usually look a bit grumpy, but curiosity almost always wins the day: Capuchin monkeys (cebinae). Their habitat stretches from Central America down to Northern Argentina. They owe their name to Portuguese explorers, who felt the monkeys’ colouring resembled the cowls worn by Capuchin friars.

It’s fascinating to note that Capuchins have quite a large brain relative to their body size. Scientists attribute this to their complex foraging techniques. They are extremely adaptable and skilled tool users – we watched them feeding time and again, even seeing them tuck into coconuts.

Howler monkeys: loud and leisurely

You often hear them long before you see them: the loud Howler monkeys (alouatta) frequently served as our natural jungle alarm clock at four in the morning. After the Woolly Spider monkeys (brachyteles), they are the largest monkeys in the New World.

A fascinating detail: They are the only New World primates to have developed trichromatic colour vision (similar to us humans). Their namesake roar, which can be heard for several kilometres, is used for communication between different groups. This makes them officially the loudest land animals on Earth! Despite their leisurely pace, they are expert climbers and often use their prehensile tail as a “fifth hand” – strong enough to support their entire body weight during a leap.

For me, monkeys are definitely animals I could watch for hours on end – no matter how many times we’ve seen them before. And honestly? Even that loud roaring at 4 am has become something quite beautiful and comforting to me. It’s the sound of the wild, and I truly hope we get to hear it for many years to come.