The descendants of the padlcats have been present in the South Cardiva island chain for around five-hundred-thousand years now. These stiflingly hot and humid tropical islands,  full of giant predatory lizards, ravaged by summer storms and prone to freshwater droughts in the cooler season proved difficult for the cats to adapt to,  and at the worst of times their presence on the islands hung on by a tether.  In addition to this, they suffered from the effects of inbreeding and low genetic diversity due to a low starting population. But these determined cats, their ancestors having survived a gruelling rafting event across the ocean, were not ready to be defeated now. Gradually their population grew over the long term and as they spread along the coast and into the islands, populations began to differ in subtle ways in response to their environments and food sources. A little under 500,000 years has been enough time for a few beneficial mutations to occur (especially where background radiation is slightly higher, such as near some fresh lava flows) and for new combinations of existing genes to present novel benefits for survival.

The "sea babies" are so named because of the rapid development of their kittens towards being able to swim. The modern domestic cat bears very altricial kittens, unable to open their eyes or hear for up to three weeks after birth, unable to walk, unable to do much of anything except crawl feebly on their belly or drink milk. They can't even go to the bathroom without their mother's assistance. But sea babies are much less helpless as a newborn. Their eyes open around the time of birth, with some kittens born with their eyes already open, while others might take a few hours to a day to open after being born. They are also able to hear their mother and hear danger, as well as respond to frights with loud, high-pitched cries to alert their mother. They aren't very mobile and still can only belly-crawl, but can do so with greater strength and are also able to lift their head.

The sea babies' growth is leaps ahead of the domestic cat, in exchange for a slightly longer gestation. Their mother has a much richer milk than that of the ancestral domestic cat, allowing the kittens to bulk up in a short space of time. For a domestic kitten, three weeks isn't much time to grow as by that point they would only start to see, hear and move around a little more actively than before (but still belly crawl). For sea babies, three weeks is enough time to develop the size, muscle condition and coordination to scamper, playfight and even swim.

Sea babies are aquiatic hunters, not as suited for catching prey on the land. Because of this their mother has to get back to hunting in the sea within a month of the kitten's birth. Historically, leaving the kittens unattended on the beach has been a huge source of kitten loss. Sea babies don't leave their kittens unattended on the beach if they can help it. They have much greater chance of survival in the water where their mother can react to danger and possibly save their kittens from would-be attackers, or deter potential attackers entirely. Because of this their mother will force them into the water early, at first into the surf just to get their feet wet, but then into deeper water as they become more confident or as her desperation for a proper meal increases. Most sea baby kittens have a well-attuned instinct for swimming, and will become adept in mere days. They reflexively know to close their nostrils and stop breathing when their head is submerged, and to surface for air when needed. However it is also a selector against individuals born less suited for the water, as this will test whether they can keep up or not.

For the first while the kittens' mother will keep a close eye on them, until her attention is turned to potential prey. Lava bombs fired into the water from a long-ago local Strombolian eruption now host various new members of algae, aquatic fungi, descendants of sea-oak, sea lettuce, mussels, sponges and prawns (some practically invisible due to their extreme transparency), bearing uncanny resemblance to their ancestral forms but with new diversity amongst them. A small semi-aquatic descendant of common lizards, a sea rope, follows them while keeping it's presence somewhat concealed by the rocks. Now with a long body that swims using side-ways undulations. They have only retained their hindlegs for mating and in some situations to assist with braking and steering. Sea ropes commonly follow sea babies because sea babies are such messy eaters they leave plenty of floating scraps for smaller animals. But  sea ropes tag along with great caution. Occasionally the sea ropes and other scavengers too become cat food. Sea ropes can survive and swim with a significant amount of tail missing, and have not lost the ability to detach their tail if it has been caught, and then regrow it again over time.

Young sea kittens don't just develop their swimming instincts early, they also begin hunting very early for a cat. Their first kills are likely to be of amphibious prawns on the beach, but it's not long before they start moving on to tiny lizards and small aquatic prawns, which are much faster in the water than on land. Their exploration into predation is much more self-driven than that of other cats, though they do still take pointers from their mother. As they grow, their doughy body becomes longer and more streamlined, allowing them to glide through water more efficiently and take on increasingly faster and more difficult prey. By time these kittens are completely self-sufficient, some kittens from other cat species are only just starting to learn to hunt. Because of this, their mother can move on to her next litter relatively soon after birthing them, with some coercion:

After picking up the scent markings of an active tom in the area, the kitten's mother no longer has any more time for them now that they are perfectly able to look after themselves. She wants to have more kittens, and that will be difficult with an older kitten around, who will present danger to new kittens by taking resources and even becoming aggressive to them due to hormonal changes in the maturing older kitten. The aggression she shows to her older kitten is just that: show. Unless the kitten is particularly stubborn there is no real physical harm done beyond a scratch or nip. It's a rite of passage for many young sea kittens, and a harsher treatment than the ancestral padlcats that arrived on the rafting event, who stayed in family groups long after the kittens were mature. This is largely down to a harsher environment that can't support as many mouths to feed and puts a lot of strain on individuals who are competing for food. What's more, the heat does not favour complex thinking. To streamline brain function, these cats have lost some of their social intelligence in favour of sharper instincts from birth. All these factors have resulted in a cat that is a little more solitary.

Sea babies are not the only padlcat descendants on the island, but they are the most aquatic, having spread up and down the coasts of the island chain, apart from the East. In the next page some of these other less aquatic descendants will be visited.