The Vision Fund did not say much about what it sees in Wag. In a statement on Tuesday, Jeffrey Housenbold, who helps oversee the fund, said only that “Wag is a clear leader in the rapidly growing global market for pet care services.”

Still, other investments by Mr. Son, the leader of the Japanese conglomerate SoftBank, suggest that he is not likely investing in Wag solely to bet on the business of keeping Fluffy content.

A little over a year into its existence, the Vision Fund has come to focus on companies that can collect and harness vast oceans of data to transform industries as diverse as medicine, food and finance.

Apart from big names like Uber, it has invested in outfits like Compass, a New York-based platform for buying and selling property; Vir Biotechnology, which researches and develops treatments for infectious diseases; and Oyo, a hotel network in India.

Wag’s app keeps track of exactly where your pooch is being taken by its walker. That makes Wag a potentially useful fount of location data. (Although, to be clear, this location data is not about Wag’s users, but about its users’ dogs.)