The space in the thoracic cavity between the concave inner surfaces of the lungs, in which (in a special pericardial cavity) the heart is located, is called the mediastinum. The thoracic cavity is lined with a serous membrane called the pleura. The lungs are enclosed in the so-called pleural cavities, which are separate in man but communicate with one another in the majority of mammals. The shape of the thoracic cavity depends upon the shape of the thorax and the position of the diaphragm.
We sell 5 hammock sizes on the Traditional Hammocks (no spreader wood bars). Therefore, the length of the hammock is the same for each size but the difference is the width. Width gives the size. The larger the size, the wider and bigger the hammock.
Some adult hamsters weigh as little as half an ounce, and some weigh as much as 10.5 ounces. Of the five species that are commonly sold as pets, the Syrian hamster is the largest and the Roborovski hamster is the smallest. Hamsters are fully grown at about 6 months of age; at 18 months of age -- when hamsters enter old age -- their weight may decrease.