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Platypuses can give a low growl when disturbed, and a range of vocalisations have been reported in captivity. [16] Size varies considerably in different regions, with average weight from 0.7 to 2.4 kg (1 lb 9 oz to 5 lb 5 oz); males have average length 50 cm (20 in), while females are the smaller at 43 cm (17 in). [21]
Egg size tends to be proportional to the size of the adult bird, [citation needed] from the half gram egg of the bee hummingbird to the 1.5 kg egg of the ostrich. Kiwis have disproportionately large eggs, up to 20% of the female's body weight. [ 18 ]
According to the observation of embryonic cells of egg, chromosome number of the itch mite is either 17 or 18. While the cause for the disparate numbers is unknown, it may arise because of an XO sex determination mechanism, where males (2n=17) lack the sex chromosome and therefore have one less chromosome than the female (2n=18). [29] [29] 32 ...
The platypus has an average body temperature of about 31 °C (88 °F) rather than the averages of 35 °C (95 °F) for marsupials and 37 °C (99 °F) for placentals. [ 30 ] [ 31 ] Research suggests this has been a gradual adaptation to the harsh, marginal environmental niches in which the few extant monotreme species have managed to survive ...
At 1.5 kg (3.3 lb) and up to 17.8 cm × 14 cm (7.0 in × 5.5 in), the ostrich egg is the largest egg of any living bird, [2]: 130 though the extinct elephant bird and some non-avian dinosaurs laid larger eggs.
The egg cell or ovum (pl.: ova) is the female reproductive cell, or gamete, [1] in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female gamete is not capable of movement (non- motile ).
However, the five species of monotreme, the platypuses and the echidnas, lay eggs. The monotremes have a sex determination system different from that of most other mammals. [ 2 ] In particular, the sex chromosomes of a platypus are more like those of a chicken than those of a therian mammal.
The platypus, a monotreme mammal, has a system of five pairs of XY chromosomes. They form a multiple chain due to homologous regions in male meiosis and finally segregates into XXXXX-sperm and YYYYY-sperm. The bird Z-like pair shows up on opposite ends of the chain. Areas homologous to the bird Z chromosome are scattered throughout X3 and X5.