PBS Kids has used several groups of mascots over the years.
Dash and Dot are two green kids with black hair and similar clothes with white shoes. They were introduced on September 6, 1999, replacing the P-Pals and were dropped on October 6, 2013 after 14 years on PBS Kids and were replaced with a redesigned and older version of Dot along with two new mascots, Dee and Del. However, some idents, promos, and bumpers still aired until March 2014, most still air today. Prior to their names, they were originally named PBS Kids Boy and PBS Kids Girl before the Miss Lori and Hooper block on Labor Day 2006. Also the 3 kids, the girl in the yellow shirt with blue shorts (Kaleigh), the boy with curly hair, the blue long shirt and black long pants (Estuardo), and another girl with a pink/purple shirt and also wearing black pants (Demi) appeared in the PBS kids funding bumpers that were used from 2000-2006.
Hooper is the third mascot of PBS Kids, and the co-host of PBS Kids Preschool Block, he was introduced on September 6, 2006. He is a brown guinea pig with circular glasses (similar to the ones that Arthur wears). Like Dash and Dot, he is a popular mascot, however, during the re-brand, some of his interstitials were still intact.
Twins Dee and Del were introduced on October 7, 2013, during the re-brand. They are Dash and Dot's new younger siblings. Their big sister, Dot, now a teenager, is always taking care of and babysitting them and their big brother, Dash is absent from the bumpers likely since he was getting too old to be an official mascot. However, Dash, still appears in the familiar PBS Kids logo and he did make a surprising return in a Word of the Week promo.
The song Brothers and Sisters which they appear in reinforces that they are siblings.