International Expeditions formed in 1980 "is the “world leader in nature travel” for one reason above all others — the superb, English-speaking naturalists and historians who guide you through Earth’s great wildlife and cultural destinations."  It is part of the TUI Travel Group of companies.
"In 1990, International Expeditions helped to form The International Ecotourism Society (TIES) by providing the major source of funding, and our founder and former president, Richard Ryel, also served as a member of the original board. TIES works to bring communities, conservation and sustainable travel together to promote ecotourism trips to natural areas, while conserving the environment and improving the well-being of local people." 
IE is a corporate sponsor for the East African Wildlife Society.