Wednesday, May 26, 2010

The red "sweat" of hippos

Nope, hippos don't sweat - not in the strictest sense, as the red "sweat" of a hippo is not secreted by sweat glands. Anyway, the "sweat" of a hippo was speculated to help control the animal's body temperature, just like the sweat we produce.

After seeing the hippos in Paya Indah Wetlands, I googled for interesting information about hippos and stumbled on an interesting article about hippo "sweat". According to the three Japanese scientists who wrote the report, the red "sweat" of hippos is secreted from "unknown subdermal glands". Whatever those are, they are not sweat glands.

When first secreted, the red "sweat" is viscous and colorless. After a couple of minutes, the secretion turns red, and eventually brown after a few hours. The Japanese research team isolated the pigments responsible for the color change in the "sweat" and named them "hipposudoric acid" (the red pigment) and "norhipposudoric acid" (the orange pigment).

What's amazing about the hippo's red "sweat" is that it is a natural sunscreen and antiseptic - thanks to the red and orange pigments! The pigments can absorb harmful ultraviolet rays (290-400 nm) which reach the ground. Also, the pigments inhibit the growth of pathogenic bacteria Pseudomonas aeruginosa and Klebsiella pneumoniae. The antibacterial role of the "sweat" probably explains why hippos manage to have scratches and wounds in their skin cured readily, rarely infected, despite spending so much time in the mud (apparently an unsanitary environment).

Journal reference:
Kimiko Hashimoto, Yoko Saikawa, and Masaya Nakata (2007) Studies on the red sweat of the Hippopotamus amphibius. Pure Appl Chem, Vol. 79, No. 4, pp. 507–517.

Monday, May 24, 2010

Paya Indah Wetlands (2) - The animals

Shots of other inhabitants of the Paya Indah Wetlands:

1. Estuarine crocodile (Crocodylus porosus)

Apparently there are three (?) crocodiles living in the crocodile enclosure. I didn't arrive on the day of feeding ,which I was told was on the weekend. But I still got to see the beasts twice. Each time when I approached the fence of the enclosure, a crocodile quickly came up to the shore, and watched me - probably thinking I would bring food, or I simply looked like food. Not sure though whether the two crocodiles I saw were the same one.

2. Hippos (Hippopotamus amphibius)

I also missed the feeding time of these three hippos. They apparently spend most of their time in the mud pool and emerge only for feeding. By the way, it smelled at their enclosure.

3. Tortoise

I spotted this tortoise near where I parked my car. It got defensive and retracted its head and limbs into its shell as it saw me approach.

4. Pelicans (Pelecanus onocrotalus)

These pelicans were moving up and down near the small pond to keep a distance from me - they were always moving in a group.

5. Painted stork (Mycteria leucocephala)

The painted stork was in the same bird enclosure as the pelicans. It just stood by itself all the time, on the other side of the pond, keeping a distance from the pelicans.

6. Geese

7. Geese and ducks in a pond

Friday, May 21, 2010

Paya Indah Wetlands (1) - Sacred lotus

I visited the Paya Indah Wetlands yesterday morning. It wasn't what I planned initially. My original plan was to visit the wetlands garden in Putrajaya. Unfortunately, I couldn't find my way around. The signs weren't helpful. And I ended up visiting the Paya Indah Wetlands instead.

The park, covering about 3100 hectares, is situated near the township of Dengkil, about 50km from Kuala Lumpur. The park has about 213 species of birds, hence a good birdwatching spot. The officer at the reception told me that the park used to be run by a private company until the Department of Wildlife and National Parks took over. She told me that besides the pelicans, crocodiles, hippopotamus, porcupines, etc, the blooming sacred lotus plants in the lakes are one big attraction to photographers.

The sign says "Teratai Lake", meaning "Sacred Lotus Lake".
On the sign are a Malay paragraph and its English translation:
"While growing from mud, it is unstained - Zhou Dunyi."
"Lotus has the remarkable ability to regulate the temperature of its flowers just as we warm blooded humans do. Maybe to heat up its dear friends the coldblooded insect pollinators."

Well, the sacred lotus is such an unusual plant in that it can regulate the temperature of its flowers. During blooming, the average temperature of the receptacle has been demonstrated to stay between 30 and 36 degree Celsius (a difference of six degrees) even when the ambient temperature has risen from 10 to 45 degree Celsius (a difference of 35 degrees)! And this amazing thermoregulatory ability is attributable to the function of a protein called alternative oxidase in the sacred lotus flowers, which is also a protein which I studied in my PhD research.

The yellow, conical or funnel-shaped thingy on the right is the receptacle, where the thermoregulating process takes place.

I checked out a few lakes in the park and it seems that they all have some sacred lotus plants growing in them.

By the way, there were lots of dragonflies near the lakes. I haven't seen so many dragonflies for a long time.