The Mothers' Day campaign has been themed around elephants to raise funds to conserve the endangered Asian elephant and its habitat.
It is designed to target those who are looking for an unusual Mothers' Day gift which will last beyond the day itself.
The ads, which feature Kiruba the Asian elephant and the line "This Mothers' Day, say it with elephants", appear on various web portals driving people to the .
Those who sign up to the programme are asked to donate a minimum of £3 a month. In return they receive an adoption pack which includes a sift toy, a fact booklet about the adopted animal and regular updates about WWF and the adopted animal over the course of the year.
±±¾©Èü³µpk10 media was bought by digital media agency i-Level.
Becki Jupp, head of acquisition at WWF-UK, said: "This is a fun campaign which should capitalise on the gifting conventions of Mothers' Day and build on our experience during the Valentines period.
"In the current economic climate, it makes sense to give a dual purpose gift that combines charitable giving to a good cause with an original and thoughtful gift for a loved one."
Marc Nohr, managing partner at Kitcatt Nohr, said: "Since we started working with WWF-UK in 2007, we have achieved great results using online as an acquisition channel.
"With the Mothers' Day campaign we are looking to test the seasonality of gifting while also boosting animal adoptions during what is traditionally a quieter quarter of the year for WWF's acquisition programme."