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Yawning Helps Lions Synchronize Groups' Movements

A lion yawns at a nature reserve on the outskirts of Pretoria June 29, 2010. ENRIQUE MARCARIAN/REUTERS
A lion yawns at a nature reserve on the outskirts of Pretoria June 29, 2010. ENRIQUE MARCARIAN/REUTERS
    Berlin, London- Asharq Al-Awsat
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Yawning Helps Lions Synchronize Groups' Movements

A lion yawns at a nature reserve on the outskirts of Pretoria June 29, 2010. ENRIQUE MARCARIAN/REUTERS
A lion yawns at a nature reserve on the outskirts of Pretoria June 29, 2010. ENRIQUE MARCARIAN/REUTERS

Watching a group of lions yawn may seem like nothing more than big, lazy cats acting sleepy, but new research suggests that these yawns may be subtly communicating some important social cues. Yawning is not only contagious among lions, but it appears to help the predators synchronize their movements, researchers report in the journal Animal Behavior.

The discovery was partially made by chance, says Elisabetta Palagi, an ethologist at the University of Pisa in Italy. While studying play behavior in spotted hyenas in South Africa, she and colleagues often had the opportunity to watch lions at the same time. And she quickly noticed that lions yawn quite frequently, concentrating these yawns in short time periods, according to the German News Agency. Yawning is ubiquitous among vertebrates, possibly boosting blood flow to the skull, cooling the brain, and aiding alertness, especially when transitioning in and out of rest, the Science News website reported. In many species — like humans, monkeys, and even parakeets— yawners can infect onlookers with their "yawn contagion," leading onlookers to yawn shortly afterward.

Over four months in 2019, the researchers closely monitored 19 lions at the Greater Makalali Private Game Reserve. The team found that lions that saw another member of the pride yawn were about 139 times as likely to yawn themselves within the next three minutes. But the yawn contagion didn't stop there. Lions that caught a yawn from another lion were 11 times as likely to mirror the movements of the original yawner than those that hadn't. This motor synchrony" involved one lion yawning, then another yawning, then the first getting up and walking around or laying back down and the other doing the same thing.

In lions, contagious yawning might be important for maintaining social cohesion, Palagi says. Yawns that help lions harmonize their group movements could help get the pride all on the same page, crucial behavior for an animal that hunts and rears offspring cooperatively. Palagi notes that yawning often marks a shift between different physiological or emotional states. So, a yawn could be a good way for an individual in a social species to communicate to group mates that it is experiencing some kind of internal change.

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How the Invasive Water Hyacinth Is Threatening Fishermen’s Livelihoods on a Popular Kenyan Lake

A heron searches for food next to abandoned fishing boats trapped in hyacinth at Central Beach in Lake Naivasha in Nakuru county, Kenya's Rift Valley, Friday, Dec. 13, 2024. (AP)
A heron searches for food next to abandoned fishing boats trapped in hyacinth at Central Beach in Lake Naivasha in Nakuru county, Kenya's Rift Valley, Friday, Dec. 13, 2024. (AP)
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How the Invasive Water Hyacinth Is Threatening Fishermen’s Livelihoods on a Popular Kenyan Lake

A heron searches for food next to abandoned fishing boats trapped in hyacinth at Central Beach in Lake Naivasha in Nakuru county, Kenya's Rift Valley, Friday, Dec. 13, 2024. (AP)
A heron searches for food next to abandoned fishing boats trapped in hyacinth at Central Beach in Lake Naivasha in Nakuru county, Kenya's Rift Valley, Friday, Dec. 13, 2024. (AP)

For someone who fishes for a living, nothing says a bad day like spending over 18 hours on a lake and taking home nothing.

Recently, a group of fishermen were said to be stranded on Kenya's popular Lake Naivasha for that long and blamed the water hyacinth that has taken over large parts of it.

“They did not realize that the hyacinth would later entrap them,” said fellow fisherman Simon Macharia. The men even lost their nets, he said.

The water hyacinth is native to South America and was reportedly introduced to Kenya in the 1980s “by tourists who brought it as an ornamental plant,” said Gordon Ocholla, an environmental scientist at Mount Kenya University.

Water hyacinth was first sighted on Lake Naivasha about 10 years ago. Now it has become a large, glossy mat that can cover swathes of the lake. To fishermen, the invasive plant is a threat to livelihoods.

Usually, the presence of water hyacinth is linked to pollution. It is known to thrive in the presence of contaminants and grows quickly, and is considered the most invasive aquatic plant species in the world, Ocholla said. It can prevent the penetration of sunlight and impact airflow, affecting the quality of aquatic life.

This has caused a drastic drop in the population of fish in Lake Naivasha and some other affected areas.

The East African Journal of Environment and Natural Resources estimated in a 2023 study that the invasion of water hyacinth in Kenyan lakes — including Africa's largest lake, Lake Victoria — has led to annual losses of between $150 million and $350 million in Kenya's fishing, transport and tourism sectors.

The fishermen at Lake Naivasha know that well.

“Previously we would catch up to 90 kilograms (198 pounds) of fish per day, but nowadays we get between 10 kilograms and 15 kilograms,” Macharia said.

This means daily earnings have dropped from $210 to $35.

Fishermen say they have tried to tackle the invasion of water hyacinth but with little success.

“It grows back faster than we can remove it,” Macharia said.

There are several ways to deal with the plant, including physically removing it, Ocholla said. Another method is introducing organisms that feed on it. Or chemicals can be sprayed to kill the plant, “but this is not favorable as it would harm other aquatic life.”

Several attempts have been made to convert the plant into a useful commodity.

“The government had built a biogas processor near the lake where we were supposed to take the hyacinth, but it has never been operational,” Macharia said. He did not know why.

Recently the fishermen, through a Kenyan start-up, began using a method that converts water hyacinth into biodegradable packaging.

HyaPak started in 2022 as a project at Egerton University in Kenya. It seeks to create environmentally friendly packaging.

“On one hand there is a problem of water hyacinth, and a problem of plastic waste pollution on the other. What we are trying to do is using one problem, the hyacinth, to solve the plastic waste pollution,” HyaPak founder Joseph Nguthiru said.

He said he created the project following a disastrous field excursion that left him and his classmates stuck on Lake Naivasha.

HyaPak has entered a partnership with the fishermen, who harvest the water hyacinth and sun-dry it for a negotiable fee. Then it is transported to the Kenya Industrial Research and Development Institute in Nairobi, where HyaPak is located.

There, it is mixed with what Nguthiru called “proprietary additives” and converted into biodegradable paper material.

HyaPak is targeting the agriculture sector, creating biodegradable bags for seedlings. The bags decompose with time, releasing nutrients that Nguthiru said are beneficial to the plants.

HyaPak works with 50 fishermen at Lake Naivasha, including Macharia. The company said it processes up to 150 kilograms of water hyacinth per week, converting it to 4,500 biodegradable packages.

Experts said scaling up such work will be a challenge.

“Such solutions and others that have been applied by similar start-ups may be promising and actually work, but if they cannot be scaled to a higher level that matches the invasiveness of the water hyacinth, then the problem will still persist,” Ocholla said.