As the years have gone by there have been many advances in the style of sleeping bags. The design stayed relatively the same since they were first invented in the 19th century up until only a short while ago. The traditional rectangular shape was popular for a substantial amount of years and it wasn’t until not that long ago that their shape started to change. What before was essentially a double duvet that had been folded in half and sealed down the side and at the bottom with a zip started to become available in a number of different shapes and sizes.Mummy Shaped Sleeping BagsThe main change in shape was from rectangular shape to the mummy style sleeping bags. As the name suggests this new shape of sleeping bag closely resembles that of the tombs used to house the dead bodies of ancient Egyptians – but don’t let that put you off, there is no chance of you being entombed for centuries in such types of bags! This new advance in shape appealed to campers on many levels. The main one being that as the sleeping bag is now fitted closely to the body it can use less material and therefore have a smaller weight and be packed down into a smaller package. This reduced pack size has probably been the main reason for the rise in popularity of mummy style sleeping bags in opposition to the regular rectangular ones they can easily be stored away when not in use and can be put in or attached to a back pack very easily barely taking up any room or weighing the down unnecessarily. Combined with the reduction in size and weight there have been many other developments in sleeping bag design. These have included the addition of hoods, pockets, left handed zips and extra levels of warmth.Sleeping Bag BrandsAs the rise in popularity of sleeping bags continues to grow there have been many more brands entering into the market. Traditional camping equipment brands like The North Face, Coleman and Outwell have been joined by newcomers such as Gelert, Redstone and Vango. Although it is worth remembering that with some brands you do end up paying more for the name so make sure you check the product specifications when shopping for a new sleeping bag. Baby Sleeping BagsAlthough most adult sleeping bags are used when camping or staying outside baby sleeping bags differ in that they are mainly used indoors. They are designed for young children and babies to sleep in to keep them warm and snug, preventing them from wriggling free from traditional blankets. Grobag and Slumbersac are two popular brands of sleeping bags for babies. These bags can be a nice transition for babies who are too old or big to sleep swaddled in a Moses basket but are not yet ready to sleep in a big cot with just a loose fitting blanket to cover them. Being wrapped in something like a Grobag can give them a sense of security and help them to sleep more readily.