Of course they do, care still needs to be taken in the sun. Even though the incidence of skin cancer is significantly lower among naturally very dark-skinned people, skin cancers, including melanoma can still occur but are often detected at a later, and far more dangerous stage.
Sun exposure can also cause damage to the eyes, such as contributing to the development of cataracts, and lips.
Cataracts have blinded around 16 million people worldwide. According to the World Health Organization, up to 20% of these may have been caused or enhanced by sun exposure, especially in countries close to the equator, such as India, Pakistan and parts of Africa etc.
High levels of UV radiation have also been linked to harmful effects on the immune system.
Infants and toddlers (say up to 4 years of age) are particularly vulnerable to UV radiation induced changes in the skin due to lower levels of melanin and a thinner stratum corneum (the outermost layer of skin). Skin thickness shows a gradual increase from birth to adulthood. The epidermis is thicker in adults than it is in children. For infants, the total skin thickness for all body sites was estimated as 660 µm based on forearm measurements for infants less than 10 years of age. For adult males, the mean skin thickness on the arms and legs was estimated as 1200 µm and on the head and trunk as 2000 µm.
Therefore, limiting direct sun exposure with hats and clothing cover when outdoors (ie when UV levels are 3 and above) is recommended regardless of skin type.
With regard to sunscreen- there is no harm for children with naturally very dark skin to apply sunscreen should they wish to. Evidence has demonstrated that sunscreen does not block significant vitamin D production and therefore may be used on all skin types.