A local guide walks on the approach to Ditwa lagoon and beach near the port of Qalensiya, the second biggest town on Yemen's Socotra island November 21, 2013. The Socotra islands, in the Arabian Sea 380 km south of mainland Yemen and 80 km west of the Horn of Africa, harbour many unique species of birds and plants and gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ANIMALS) 

The approach to Ditwa lagoon and beach is pictured near the port of Qalensiya, the second biggest town on Yemen's Socotra island, November 21, 2013. The Socotra islands, in the Arabian Sea 380 km south of mainland Yemen and 80 km west of the Horn of Africa, harbour many unique species of birds and plants and gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

A woman sits on the road to Homhil of the Socotra islands November 21, 2013. The Socotra islands, in the Arabian Sea 380 km south of mainland Yemen and 80 km west of the Horn of Africa, harbour many unique species of birds and plants and gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ANIMALS) 

Dragon's Blood trees, known locally as Dam al-Akhawain or blood of the two brothers, are pictured on Socotra island November 21, 2013. The Socotra islands, in the Arabian Sea 380 km south of mainland Yemen and 80 km west of the Horn of Africa, harbour many unique species of birds and plants and gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

A man and his wife milk a cow on the road to Homhil of the Socotra islands November 21, 2013. The Socotra islands, in the Arabian Sea 380 km south of mainland Yemen and 80 km west of the Horn of Africa, harbour many unique species of birds and plants and gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ANIMALS) 

A view shows Hadibu city on the capital island of Socotra November 21, 2013. The Socotra islands, in the Arabian Sea 380 km south of mainland Yemen and 80 km west of the Horn of Africa, harbour many unique species of birds and plants and gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL CITYSCAPE) 

Tourists swim at the Dihamri PA beach of Socotra island November 20, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

Socotran "desert roses", whose obese trunks are adapted to store water, stand on a hillside in Wadi Diksam on Socotra island November 20, 2013. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site.REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

Girls are pictured at their house on Socotra island November 19, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site.REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL SOCIETY) 

Socotran "desert roses", whose obese trunks are adapted to store water, stand on a hillside in Wadi Diksam on Socotra island November 19, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

Girls stand during the morning assembly at their school on Socotra island November 19, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL EDUCATION SOCIETY) 

A woman stands with her cows on Socotra island November 19, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: ANIMALS TRAVEL ENVIRONMENT) 

Socotran "desert roses", whose obese trunks are adapted to store water, stand on a hillside in Wadi Diksam on Socotra island November 19, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

A car is pictured at the mouth of Dogub cave on Socotra island November 19, 2013. Socotra is located in the Arabian Sea, 380 km south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, gained UNESCO recognition in July 2008 as a world natural heritage site. REUTERS/Mohamed al-Sayaghi (YEMEN - Tags: TRAVEL ENVIRONMENT) 

The approach to Ditwa lagoon and beach near the port of Qalensiya, the second biggest town on Yemen's Socotra island in the Arabian Sea February 1, 2008. Now that Socotra's long isolation has been eroded, Socotra faces the challenge of how to conserve its natural treasures while opening up to tourism and improving life for its 50,000 inhabitants. REUTERS/ Alistair Lyon (YEMEN) 

Noh Maalha, a Socotri goatherd, stands next to a Dragon's Blood tree in the compound of his house February 1, 2008. Evolution has run riot on Yemens windy isles of Socotra, whose dizzing cliffs, jagged peaks and exotic plants entice the imagination to do the same. REUTERS/ Alistair Lyon (YEMEN) 

Socotri fishermen head out to sea from the port of Qalensiya, the second biggest town on Yemen's island of Socotra February 1, 2008. To match feature YEMEN-SOCOTRA
REUTERS/ Alistair Lyon (YEMEN) 

A tourist swims in a natural rock pool in a river on the island of Socotra February 1, 2008. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, may gain UNESCO recognition in July as a world natural heritage site. Picture taken on February 1, 2008. To match feature YEMEN-SOCOTRA REUTERS/Alistair Lyon/Files (YEMEN) 

A local guide stands at the mouth of Di Gob cave on Socotra island February 1, 2008. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, may gain UNESCO recognition in July as a world natural heritage site. Picture taken on February 1, 2008. To match feature YEMEN-SOCOTRA REUTERS/Alistair Lyon/Files (YEMEN) 

A girl swings on a rope in the fishing port of Qalensiya, the second biggest town on Socotra island February 1, 2008. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, may gain UNESCO recognition in July as a world natural heritage site. Picture taken on February 1, 2008. To match feature YEMEN-SOCOTRA REUTERS/Alistair Lyon/Files (YEMEN) 

Dragon's Blood trees (L) and Socotran "desert roses" stand on a hillside in the protected area of Homhill on Socotra island February 1, 2008. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, may gain UNESCO recognition in July as a world natural heritage site. Picture taken on February 1, 2008. To match feature YEMEN-SOCOTRA REUTERS/Alistair Lyon/Files (YEMEN) 

Socotran "desert roses", whose obese trunks are adapted to store water, stand on a hillside in Wadi Diksam on Socotra island February 1, 2008. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, may gain UNESCO recognition in July as a world natural heritage site. Picture taken on February 1, 2008. To match feature YEMEN-SOCOTRA REUTERS/Alistair Lyon/Files (YEMEN) 

Children play among fishing boats on the beach at Qalensiya, the second biggest town on Socotra island February 1, 2008. Socotra is located in the Arabian Sea, 380 km (238 miles) south of mainland Yemen and 80 km west of the Horn of Africa. The Socotra islands, which harbour many unique species of birds and plants, may gain UNESCO recognition in July as a world natural heritage site. Picture taken on February 1, 2008. To match feature YEMEN-SOCOTRA REUTERS/ Alistair Lyon/Files (YEMEN)