Hairs and pigments keep giant herbs hot in the cold

[This story first ran on BBC Earth, 16 December 2017]

For many people, New Zealand sits in a far corner of the world. But if you wish to visit the country’s most remote island, you would have to sail south of the mainland for 600 km into the Antarctic Ocean. At the end of the almost three-day journey, you would reach New Zealand’s southern-most territory, Campbell Island.

The island is cold, wet and windy. Temperatures rarely climb above 10 Celsius; every day is cloudy, and on most days the sun peeks through for less than an hour; strong winds (> 30km/h) sweep the island. The drizzle never seems to end. Although Campbell Island received UNESCO World Heritage Site status in 1998 for its unique biodiversity, nobody is offering tour packages.

In other regions of the world where high winds and low temperatures prevail, plants stay small. Insects pollinators are few too, so flowering plants tend to grow plain-coloured flowers and rely on self- or wind-pollination. Some plants on Campbell Island however, buck this general trend.


Robbers Force Leopards Up Trees

[This story first ran on BBC Earth, 24 April 2017]


Many animals, including Africa’s Big Five, roam the savannas of the Sabi Sand Game Reserve in South Africa. Sometimes, these animals turn up in unexpected places. Such as the young giraffe that game guides found up in a tree—hung over a fork, dead.

A large male leopard straddled the giraffe, its mouth blood red. Apparently, the leopard had hoisted the giraffe several meters up the tree. The cat feasted for a few days, leaving only bones, skin and bits of flesh scattered around.

The giraffe weighed 300 kg, about five times heavier than its killer. To match the leopard’s strength, a man would have to heave almost 2000 Big-Macs[1] up two floors in one go.


[1] Average American adult weighs 80kg; a Big Mac weighs 0.22kg. So, 5*80kg = 400kg ~= 1820 Big Macs.


A Place For Teeth and Claws

[This story first ran on BBC Earth, 17 May 2017]

In late March 1995, Yellowstone National Park, United States of America, received a special delivery. Fourteen gray wolves (Canis lupus), flown in two months ago from the Canadian Rockies, were released into the park[1]. Neighbouring Idaho received fifteen wolves. These forests had not heard wolf howls for sixty years, since wolves were exterminated by 1930s. Scientists had intended to reintroduce and conserve gray wolves in their original habitats. They did not foresee that the wolves, with blood on their teeth and claws, would restore leaves to the trees.

The wolves quickly reclaimed their spot as top predator. Ecologist William Ripple[2] of Oregon State University has been studying the wolves since their return. He found that within a decade of their release, the wolves had cut elk—their main prey—numbers by half[3]. The surviving elks avoided the wolves’ core range and stayed on the periphery. Woody trees like aspen and willow, chewed and trimmed by zealous elks, now grew tall and lush.


[1] Bangs, E.E., and Fritts, S.H. (1996). Reintroducing the gray wolf to central Idaho and Yellowstone National Park. Wildlife Society Bulletin 24, 402–413.


[3] Ripple, W.J., and Beschta, R.L. (2012). Trophic cascades in Yellowstone: The first 15 years after wolf reintroduction. Biological Conservation 145, 205–213.